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Feed provided by Bulletin of the Iranian Mathematical Society. Click to visit.Bulletin of the Iranian Mathematical Society
http://bims.iranjournals.ir/article_1151_89.html
Tue, 29 Aug 2017 19:30:00 +0100A Special Issue in Honor of Professor Freydoon Shahidi on the Occasion of His Seventieth Birthday
http://bims.iranjournals.ir/article_1152_89.html
Tue, 29 Aug 2017 19:30:00 +0100Filtrations of smooth principal series and Iwasawa modules
http://bims.iranjournals.ir/article_1153_89.html
Let $G$ be a reductive $p$-adic group‎. ‎We consider the general question‎ ‎of whether the reducibility of an induced representation can be detected in a‎ ‎``co-rank one‎" ‎situation‎. ‎For smooth complex representations induced from supercuspidal‎ ‎representations‎, ‎we show that a sufficient condition is the existence of a subquotient‎ ‎that does not appear as a subrepresentation‎. ‎An important example is the Langlands' quotient‎. ‎In addition‎, ‎we study the same general question for continuous principal series on $p$-adic Banach spaces‎. ‎Although we do not give an answer in this case‎, ‎we describe‎ ‎a related filtration on the corresponding Iwasawa modules‎. Tue, 29 Aug 2017 19:30:00 +0100Symmetric powers and the Satake transform
http://bims.iranjournals.ir/article_1154_89.html
‎This paper gives several examples of the basic functions‎ ‎introduced in recent years by Ng^o‎. ‎These are mainly‎ ‎conjectures based on computer experiment‎. Tue, 29 Aug 2017 19:30:00 +0100Globally analytic $p$-adic representations of the pro--$p$--Iwahori subgroup of $GL(2)$ and ...
http://bims.iranjournals.ir/article_1155_89.html
This paper extends to the pro-$p$ Iwahori subgroup of $GL(2)$ over an unramified finite extension of $mathbb{Q}_p$ the presentation of the Iwasawa algebra obtained earlier by the author for the congruence subgroup of level one of $SL(2‎, ‎mathbb{Z}_p)$‎. ‎It then describes a natural base change map between the Iwasawa algebras or more correctly‎, ‎as it turns out‎, ‎between the global distribution algebras on the associated rigid-analytic spaces‎. ‎In a forthcoming paper this will be applied to $p$-adic representation theory‎.Tue, 29 Aug 2017 19:30:00 +0100Diffie-Hellman type key exchange protocols based on isogenies
http://bims.iranjournals.ir/article_1156_89.html
‎In this paper‎, ‎we propose some Diffie-Hellman type key exchange protocols using isogenies of elliptic curves‎. ‎The first method which uses the endomorphism ring of an ordinary elliptic curve $ E $‎, ‎is a straightforward generalization of elliptic curve Diffie-Hellman key exchange‎. ‎The method uses commutativity of the endomorphism ring $ End(E) $‎. ‎Then using dual isogenies‎, ‎we propose a second method‎. ‎This case uses the endomorphism ring of an elliptic curve $ E $‎, ‎which can be ordinary or supersingular‎. ‎We extend this method using isogenies between two elliptic curves $ E $ and $ E' $‎. ‎Our methods have the security level of that of [D‎. ‎Jao and L‎. ‎De Feo‎, ‎Towards quantum-resistant cryptosystems from supersingular elliptic curve isogenies‎, J‎. ‎Math‎. ‎Cryptol. 8 (2014)‎, ‎no‎. ‎3‎, ‎209--247]‎, ‎with the advantage of transmitting less information between two parties‎.
Tue, 29 Aug 2017 19:30:00 +0100Theta functions on covers of symplectic groups
http://bims.iranjournals.ir/article_1157_89.html
We study the automorphic theta representation $Theta_{2n}^{(r)}$ on the $r$-fold cover of the symplectic group $Sp_{2n}$‎. ‎This representation is obtained from the residues of Eisenstein series on this group‎.
‎If $r$ is odd‎,
‎$nle r <2n$‎, ‎then under a natural hypothesis on the theta representations‎, ‎we show that‎
‎$Theta_{2n}^{(r)}$ may be used to construct a globally generic representation‎
‎$sigma_{2n-r+1}^{(2r)}$ on the $2r$-fold cover of $Sp_{2n-r+1}$‎. ‎Moreover‎, ‎when $r=n$ the‎
‎Whittaker functions of this representation attached to factorizable data‎ ‎are factorizable‎, ‎and the unramified local factors may be computed in terms of $n$-th order Gauss sums‎. ‎If $n=3$ we prove these results‎, ‎which in that case pertain to the six-fold cover of $Sp_4$‎, ‎unconditionally‎. ‎We expect that in fact the representation constructed here‎, ‎$sigma_{2n-r+1}^{(2r)}$‎, ‎is precisely $Theta_{2n-r+1}^{(2r)}$; that‎ ‎is‎, ‎we conjecture relations between theta representations on different covering groups‎.
Tue, 29 Aug 2017 19:30:00 +0100Behavior of $R$-groups for $p$-adic inner forms of quasi-split special unitary groups
http://bims.iranjournals.ir/article_1158_89.html
‎We study $R$-groups for $p$-adic inner forms of quasi-split special unitary groups‎. ‎We prove Arthur's conjecture‎, ‎the isomorphism between the Knapp-Stein $R$-group and the Langlands-Arthur $R$-group‎, ‎for quasi-split special unitary groups and their inner forms‎. ‎Furthermore‎, ‎we investigate the invariance of the Knapp-Stein $R$-group within $L$-packets and between inner forms‎. ‎This work is applied to transferring known results in the second-named author's earlier work for quasi-split special unitary groups to their non-quasi-split inner forms‎.Tue, 29 Aug 2017 19:30:00 +0100Strong exponent bounds for the local Rankin-Selberg convolution
http://bims.iranjournals.ir/article_1159_89.html
Let $F$ be a non-Archimedean locally compact field‎. ‎Let $sigma$ and $tau$ be finite-dimensional representations of the Weil-Deligne group of $F$‎. ‎We give strong upper and lower bounds for the Artin and Swan exponents of $sigmaotimestau$ in terms of those of $sigma$ and $tau$‎. ‎We give a different lower bound in terms of $sigmaotimeschecksigma$ and $tauotimeschecktau$‎. ‎Using the Langlands correspondence‎, ‎we obtain the bounds for Rankin-Selberg exponents‎.Tue, 29 Aug 2017 19:30:00 +0100On tensor product $L$-functions and Langlands functoriality
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‎In the spirit of the Langlands proposal on Beyond Endoscopy ‎we discuss the explicit relation between the Langlands functorial transfers and automorphic $L$-functions‎. ‎It is well-known that the poles of the $L$-functions have deep impact to the Langlands functoriality‎. ‎Our discussion also‎ ‎includes the meaning of the central value of the tensor product $L$-functions in terms of the Langlands functoriality‎. ‎This‎ ‎leads to the theory of the twisted automorphic descents for cuspidal automorphic representations of general classical groups‎. Tue, 29 Aug 2017 19:30:00 +0100The residual spectrum of $U(n,n)$; contribution from Borel subgroups
http://bims.iranjournals.ir/article_1161_89.html
‎In this paper we study the residual spectrum of the quasi-split unitary group $G=U(n,n)$ defined over a number field $F$‎, ‎coming from the Borel subgroups‎, ‎$L_{dis}^2(G(F)backslash G(Bbb A))_T$‎. ‎Due to lack of information on the local results‎, ‎that is‎, ‎the image of the local intertwining operators of the principal series‎, ‎our results are incomplete‎. ‎However‎, ‎we describe a conjecture on the residual spectrum and prove a certain special case by using the Knapp-Stein $R$-group of the unitary group‎.Tue, 29 Aug 2017 19:30:00 +0100Computing local coefficients via types and covers: the example of $SL(2)$
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‎We illustrate a method of computing Langlands-Shahidi local coefficients via the theory of types and covers‎. ‎The purpose of this paper is to illustrate a method of computing the Langlands-Shahidi local coefficients using the theory of types and covers.Tue, 29 Aug 2017 19:30:00 +0100On the analytic properties of intertwining operators I: global normalizing factors
http://bims.iranjournals.ir/article_1163_89.html
‎We provide a uniform estimate for the $L^1$-norm (over any interval of bounded length) of the logarithmic derivatives‎ ‎of global normalizing factors associated to intertwining operators for the following reductive groups over number fields‎: ‎inner forms of $operatorname{GL}(n)$; quasi-split classical groups and their similitude groups; the exceptional group $G_2$‎. ‎This estimate is a key ingredient in the analysis of the spectral side of Arthur's trace formula‎. ‎In particular‎, ‎it is applicable to the limit multiplicity problem studied by the authors in earlier papers‎.Tue, 29 Aug 2017 19:30:00 +0100Caractérisation des paramètres d'Arthur, une remarque
http://bims.iranjournals.ir/article_1164_89.html
‎In The endoscopic classification of representations‎‎, ‎J‎. ‎Arthur has proved the Langlands' classification for discrete series of p-adic classical groups‎. ‎This uses endoscopy and twisted endoscopy‎. ‎In this very short note‎, ‎we remark that the normalization ‎$‎rm‎grave{a}‎$‎ la Langlands-Shahidi of the intertwining operators‎, ‎allows to avoid endoscopy‎. ‎This is based on the intertwining relation which is a very important point of this book‎.Tue, 29 Aug 2017 19:30:00 +0100Distinguished positive regular representations
http://bims.iranjournals.ir/article_1165_89.html
Let $G$ be a tamely ramified reductive $p$-adic‎ ‎group‎. ‎We study distinction of a class of irreducible admissible representations‎ ‎of $G$ by the group of fixed points $H$ of an involution‎ ‎of $G$‎. ‎The representations correspond to $G$-conjugacy classes of‎ ‎pairs $(T,phi)$‎, ‎where $T$ is a‎ ‎tamely ramified maximal torus of $G$ and $phi$ is a quasicharacter‎ ‎of $T$ whose restriction to the maximal pro-$p$-subgroup‎ ‎satisfies a regularity condition‎. ‎Under mild restrictions on the residual characteristic of‎ ‎$F$‎, ‎we derive necessary conditions for $H$-distinction of‎ ‎a representation corresponding to $(T,phi)$‎, ‎expressed in terms of properties of $T$ and $phi$‎ ‎relative to the involution‎. ‎We prove that if an $H$-distinguished representation arises from‎ ‎a pair $(T,phi)$ such that $T$ is stable under the involution and‎ ‎compact modulo $(Tcap H)Z$ (here‎, ‎$Z$ is the centre of‎ ‎$G$)‎, ‎then the representation is $H$-relatively supercuspidal‎.Tue, 29 Aug 2017 19:30:00 +0100On the transcendence of certain Petersson inner products
http://bims.iranjournals.ir/article_1166_89.html
‎We show that for all normalized Hecke eigenforms $f$‎ ‎with weight one and of CM type‎, ‎the number $(f,f)$ where $(cdot‎, ‎cdot )$ denotes‎ ‎the Petersson inner product‎, ‎is a linear form in logarithms and‎ ‎hence transcendental‎.Tue, 29 Aug 2017 19:30:00 +0100Endoscopy and the cohomology of $GL(n)$
http://bims.iranjournals.ir/article_1167_89.html
Let $G = {rm Res}_{F/mathbb{Q}}(GL_n)$ where $F$ is a number field‎. ‎Let $S^G_{K_f}$ denote an ad`elic locally symmetric space for some level structure $K_f.$ Let ${mathcal M}_{mu,{mathbb C}}$ be an algebraic irreducible representation of $G({mathbb R})$ and we let $widetilde{mathcal{M}}_{mu,{mathbb C}}$ denote the associated sheaf on $S^G_{K_f}.$ The aim of this paper is to classify the data $(F,n,mu)$ for which cuspidal cohomology of $G$ with $mu$-coefficients‎, ‎denoted $H^{bullet}_{rm cusp}(S^G_{K_f}‎, ‎widetilde{mathcal{M}}_{mu,{mathbb C}})$‎, ‎is nonzero for some $K_f.$ We prove nonvanishing of cuspidal cohomology when $F$ is a totally real field or a totally imaginary quadratic extension of a totally real field‎, ‎and also for a general number field but when $mu$ is a parallel weight‎.Tue, 29 Aug 2017 19:30:00 +0100On Atkin-Lehner correspondences on Siegel spaces
http://bims.iranjournals.ir/article_1168_89.html
‎We introduce a higher dimensional Atkin-Lehner theory for‎ ‎Siegel-Parahoric congruence subgroups of $GSp(2g)$‎. ‎Old‎ ‎Siegel forms are induced by geometric correspondences on Siegel‎ ‎moduli spaces which commute with almost all local Hecke algebras‎. ‎We also introduce an algorithm to get equations for moduli spaces of‎ ‎Siegel-Parahoric level structures‎, ‎once we have equations for prime levels and square prime levels‎ ‎over the level one Siegel space‎. ‎This way we give equations for an infinite tower of Siegel spaces‎ ‎after N‎. ‎Elkies who did the genus one case‎. Mon, 31 Jul 2017 19:30:00 +0100Spatial statistics for lattice points on the sphere I: Individual results
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‎We study the spatial distribution of point sets on the sphere obtained from the representation of a large integer as a sum of three integer squares‎. ‎We examine several statistics of these point sets‎, ‎such as the electrostatic potential‎, ‎Ripley's function‎, ‎the variance of the number of points in random spherical caps‎, ‎and the covering radius‎. ‎Some of the results are conditional on the Generalized Riemann Hypothesis‎. ‎ Tue, 29 Aug 2017 19:30:00 +0100On local gamma factors for orthogonal groups and unitary groups
http://bims.iranjournals.ir/article_1170_89.html
‎In this paper‎, ‎we find a relation between the proportionality factors which arise from the functional equations of two families of local Rankin-Selberg convolutions for‎ ‎irreducible admissible representations of orthogonal groups‎, ‎or unitary groups‎. ‎One family is that of local integrals of the doubling method‎, ‎and the other family is‎ ‎that of local integrals expressed in terms of spherical Bessel models‎. Tue, 29 Aug 2017 19:30:00 +0100Some bounds on unitary duals of classical groups - non-archimeden case
http://bims.iranjournals.ir/article_1171_89.html
‎We first give bounds for domains where the unitarizabile subquotients can show up in the parabolically induced representations of classical $p$-adic groups‎. ‎Roughly‎, ‎they can show up only if the‎ ‎central character of the inducing irreducible cuspidal representation is dominated by the‎ ‎square root of the modular character of the minimal parabolic subgroup‎. ‎For unitarizable subquotients supported by a fixed parabolic subgroup‎, ‎or in a specific Bernstein component‎, ‎a more precise bound is given‎. ‎For the reductive groups of rank at least two‎, ‎the trivial representation is always isolated in the unitary dual (D‎. ‎Kazhdan)‎. ‎Still‎, ‎we may ask if the level of isolation is higher in the case of the automorphic duals‎, ‎as it is a case in the rank one‎. ‎We show that the answer is negative to this question for symplectic $p$-adic groups‎.Tue, 29 Aug 2017 19:30:00 +0100Compact and weakly compact multipliers of locally compact quantum group
http://bims.iranjournals.ir/article_950_0.html
A locally compact group G is compact if and only if its convolution algebra has anon-zero (weakly) compact multiplier. Dually, G is discrete if and only if its Fourier algebra hasa non-zero (weakly) compact multiplier. Also, G is compact (respectively, amenable) if and onlyif the second dual of its convolution algebra equipped with the first Arens product has a non-zero (weakly) compact left (respectively, right) multiplier. We prove the non-commutative versions of these results in the case of locally compact quantum groups.Sun, 19 Feb 2017 20:30:00 +0100Benson's algorithm for nonconvex multiobjective problems via nonsmooth Wolfe duality
http://bims.iranjournals.ir/article_968_0.html
In this paper, we propose an algorithm to obtain an approximation set of the (weakly) nondominated points of nonsmooth multiobjective optimization problems with equality and inequality constraints. We use an extension of the Wolfe duality to construct the separating hyperplane in Benson’s outer algorithm for multiobjective programming problems with subdifferentiable functions. We also formulate an infinitive approximation set of the (weakly) nondominated points of biobjective optimization problems. Moreover, we provide some numericalexamples to illustrate the advantage of our algorithm.Sun, 19 Feb 2017 20:30:00 +0100Critical fixed point theorems in Banach algebras under weak topology features
http://bims.iranjournals.ir/article_969_0.html
In this paper, we establish some new critical fixed point theorems for the sum $AB+C$ in a Banach algebra relative to the weak topology, where $frac{I-C}{A}$ allows to be noninvertible. In addition, a special class of Banach algebras will be considered.Sun, 19 Feb 2017 20:30:00 +0100Existence of ground state solutions for a class of nonlinear elliptic equations with fast ...
http://bims.iranjournals.ir/article_975_0.html
This paper is devoted to get a ground state solution for a class of nonlinear elliptic equations with fast increasing weight. We apply the variational methods to obtain the existence of ground state solutions when nonlinearity is superlinear and asymptotically linear at infinity, respectively.Sun, 19 Feb 2017 20:30:00 +0100The norm of pre-Schwarzian derivatives on bi-univalent functions of order $\alpha$
http://bims.iranjournals.ir/article_976_0.html
In the present investigation, we give the best estimates for the norm of the pre-Schwarzian derivative $ T_{f}(z)=dfrac{f^{''}(z)}{f^{'}(z)} $ for bi-starlike functions and a new subclass of bi-univalent functions of order $ alpha $, where $$Vert T_{f} Vert= textit{sup}_{|z|Sun, 19 Feb 2017 20:30:00 +0100On annihilator ideals in skew polynomial rings
http://bims.iranjournals.ir/article_977_0.html
This article examines annihilators in the skew polynomial ring $R[x;alpha,delta]$. A ring is strongly right $AB$ if everynon-zero right annihilator is bounded. In this paper, we introduce and investigate a particular class of McCoy rings which satisfy Property ($A$) and the conditions asked by P.P. Nielsen. We assume that $R$ is an ($alpha$,$delta$)-compatible ring, and prove that, if $R$ is nil-reversible then the skew polynomial ring $R[x;alpha,delta]$is strongly right $AB$. It is also shown that, every right duo ring with an automorphism $alpha$ is skew McCoy. Moreover, if $R$ is strongly right $AB$ and skew McCoy, then $R[x;alpha]$ and $R[x;delta]$ have right Property ($A$).Sun, 19 Feb 2017 20:30:00 +0100Diagonal arguments and fixed points
http://bims.iranjournals.ir/article_979_0.html
A universal schema for diagonalization was popularized by N. S. Yanofsky (2003), based on a pioneering work of F. W. Lawvere (1969), in which the existence of a (diagonolized-out and contradictory) object implies the existence of a fixed-point for a certain function. It was shown that many self-referential paradoxes and diagonally proved theorems can fit in that schema. Here, we fit more theorems in the universal schema of diagonalization, such as Euclid's proof for the infinitude of the primes and new proofs of G. Boolos (1997) for Cantor's theorem on the non-equinumerosity of a set with its powerset. Then, in Linear Temporal Logic, we show the non-existence of a fixed-point in this logic whose proof resembles the argument of Yablo's paradox (1985, 1993). Thus, Yablo's paradox turns for the first time into a genuine mathematico-logical theorem in the framework of Linear Temporal Logic. Again the diagonal schema of the paper is used in this proof; and it is also shown that G. Priest's inclosure schema (1997) can fit in our universal diagonal/fixed-point schema. We also show the existence of dominating (Ackermann-like) functions (which dominate a given countable set of functions, such as primitive recursive functions) in the schema.Sun, 19 Feb 2017 20:30:00 +0100Order-type existence theorem for second order nonlocal problems at resonance
http://bims.iranjournals.ir/article_982_0.html
This paper gives an abstract order-type existence theorem for second order nonlocal boundary value problems at resonance and obtain existence criteria for at least two positive solutions, where $f$ is a continuous function. Our results generalize or extend related results in the literature and give a positive answer to the question raised in the literature. An example is given to illustrate the new results.Sun, 19 Feb 2017 20:30:00 +0100Existence and blow-up of solution of Cauchy problem for the sixth order damped Boussinesq equation
http://bims.iranjournals.ir/article_986_0.html
‎In this paper‎, ‎we consider the existence and uniqueness of the global solution for the sixth-order damped Boussinesq equation‎. ‎Moreover‎, ‎the finite-time blow-up of the solution for the equation is investigated by the concavity method‎.Mon, 20 Feb 2017 20:30:00 +0100On two classes of third order boundary value problems with finite spectrum
http://bims.iranjournals.ir/article_987_0.html
The spectral analysis of two classes of third order boundary value problems is investigated. For every positive integer m we construct two classes of regular third order boundary value problems with at most 2m+1 eigenvalues, counting multiplicity. These kinds of finite spectrum results are previously known only for even order boundary value problems.Mon, 20 Feb 2017 20:30:00 +0100Affinization of Segre products of partial linear spaces
http://bims.iranjournals.ir/article_1010_0.html
Hyperplanes and hyperplane complements in the Segre product of partial linear spaces are investigated. The parallelism of such a complement is characterized in terms of the point-line incidence. Assumptions, under which the automorphisms of the complement are the restrictions of the automorphisms of the ambient space, are given. An affine covering for the Segre product of Veblenian gamma spaces is established. A general construction that produces non-degenerate hyperplanes in the Segre product of partial linear spaces embeddable into projective space is introduced.Mon, 20 Feb 2017 20:30:00 +0100A new one-step iterative process for approximating common fixed points of a countable family of ...
http://bims.iranjournals.ir/article_1011_0.html
In this paper, we propose a new one-step iterative process for a countable family of quasi-nonexpansive multi-valued mappings in a CAT(0) space. We also prove $Delta$ and strong convergence theorems of the proposed iterative process under some control conditions. Our main results extend and generalize many results in the literature.Mon, 20 Feb 2017 20:30:00 +0100A new characterization of $L_2(q)$ by the largest element orders
http://bims.iranjournals.ir/article_1012_0.html
‎We characterize finite simple groups $L_2(q)$ by both the group orders and the largest‎ ‎element orders‎, ‎where $q$ is a prime or $q=2^a$ satisfying that $2^a+1$ or $2^a-1$ is a prime‎.Mon, 20 Feb 2017 20:30:00 +0100A radical extension of the category of $S$-sets
http://bims.iranjournals.ir/article_1013_0.html
Let S-Set be the category of $S$-sets, sets together with the actions of a semigroup $S$ on them. And, let S-Pos be the category of $S$-posets, posets together with the actions compatible with the orders on them. In this paper we show that the category S-Pos is a radical extension of S-Set; that is there is a radical on the category S-Pos, the order desolator radical, whose torsion-free class is S-Set. To do this, first we give a precise definition of a radical on the category S-Posand construct some functors between the above mentioned categories and finally we show that S-Pos is a radical extension of S-Set.Mon, 20 Feb 2017 20:30:00 +0100A numerical method for discrete fractional--order Chemostat model derived from nonstandard ...
http://bims.iranjournals.ir/article_1014_0.html
‎In this paper‎, ‎the fractional--order form of three dimensional chemostat model with variable yields is introduced‎. ‎The stability analysis of this fractional system is discussed in detail‎. ‎In order to study the dynamic behaviours of mentioned fractional system‎, ‎the well known nonstandard (NSFD) scheme is implemented‎. ‎The proposed NSFD scheme is compared with the forward Euler and fourth order Runge--Kutta methods‎. ‎Numerical results show that the NSFD approach is easy and accurate when applied to fractional--order chemostat model.Mon, 20 Feb 2017 20:30:00 +0100On characterizations of hyperbolic harmonic Bloch and Besov spaces
http://bims.iranjournals.ir/article_1015_0.html
We define hyperbolic harmonic $omega$-$alpha$-Bloch space $mathcal{B}_omega^alpha$ in the unit ball $IB$ of $IR^n$ and characterize it in terms of $frac{omegabig((1-|x|^2)^{beta}(1-|y|^2)^{alpha-beta}big)|f(x)-f(y)|}{[x,y]^gamma|x-y|^{1-gamma} }$, where $0leq gammaleq 1$. Similar results are extended tolittle $omega$-$alpha$-Bloch and Besov spaces. These obtained characterizations generalize the corresponding ones due to G. Ren and U. K"{a}hler in cite{RK,RK1}.Mon, 20 Feb 2017 20:30:00 +0100On the character space of Bananch vector-valued function algebras
http://bims.iranjournals.ir/article_1016_0.html
Given a compact space $X$ and a commutative Banach algebra $A$, the character spaces of $A$-valued function algebras on $X$ are investigated. The class of natural $A$-valued function algebras, those whose characters can be described by means of characters of $A$ and point evaluation homomorphisms, is introduced and studied. For an admissible Banach $A$-valued function algebra $mathcal{A}$ on $X$, conditions under which the character space $M(mathcal{A})$ is homeomorphic to $M(mathfrak{A}) times M(A)$ are presented, where $mathfrak{A}=C(X) cap mathcal{A}$ is the subalgebra of $mathcal{A}$ consisting of scalar-valued functions. An illustration of the results is given by some examples.Mon, 20 Feb 2017 20:30:00 +0100On some generalized recurrent manifolds
http://bims.iranjournals.ir/article_1017_0.html
The object of the present paper is to introduce and study a type of non-flat semi-Riemannian manifolds, called, super generalized recurrent manifolds which generalizes both the notion of hyper generalized recurrent manifolds and weakly generalized recurrent manifolds. The nature of associated 1-forms of a super generalized recurrent manifold is determined and it is proved that on a Roter type manifold such a notion is equivalent to the notion of generalized Ricci-recurrent manifold. We also obtain a sufficient condition for a super generalized recurrent manifold to be a semisymmetric one and the existence of such notion is ensured by a proper example.Mon, 20 Feb 2017 20:30:00 +0100On pm$^+$ and finite character bi-amalgamation
http://bims.iranjournals.ir/article_1018_0.html
Let $f:Arightarrow B$ and $g:A rightarrow C$ be two ring homomorphisms and let $J$ and $J'$ be two ideals of $B$ and $C$, respectively, such that $f^{-1}(J)=g^{-1}(J')$. The bi-amalgamation of $A$ with $(B,C)$ along $(J,J')$ with respect of $(f,g)$ is subring of $Btimes C$ given by $$Abowtie^{f,g}(J,J')={(f(a)+j,g(a)+j')/ a in A, (j,j') in Jtimes J'} $$In this paper we study the transference of $pm^{+}$, $pm$ and finite character ring-properties in the bi-amalgamation.Mon, 20 Feb 2017 20:30:00 +0100Study on dimensions of modules
http://bims.iranjournals.ir/article_1019_0.html
In this article we study relations between some algebraic operations such as tensor product, localization and dual modules from one hand and some well-known dimensions such as uniform dimension, hollow dimension and type dimension from the other hand. Some applications in ring of all real valued continuous functions over a completely regular space $X$, $C(X)$, have been discovered as well.Mon, 20 Feb 2017 20:30:00 +0100Efficient quadrature rules for a class of cordial Volterra integral equations: A comparative study
http://bims.iranjournals.ir/article_1020_0.html
A natural algorithm with an optimal order of convergence is proposed for numerical solution of a class of cordial weakly singular Volterra integral equations. The equations of this class appear in heat conduction problems with mixed boundary conditions. The algorithm is based on a representation of the solution and compound Gaussian quadrature rules with graded meshes. A comparative study is carried out, which points out that the proposed method is the most efficient one among other existing methods. In fact, the results of this paper introduce a most-efficient decisive-choice for computing the solution of the heat conduction model.Mon, 20 Feb 2017 20:30:00 +0100On certain maximality principles
http://bims.iranjournals.ir/article_1021_0.html
We present streamlined proofs of certain maximality principles studied by Hamkins and Woodin. Moreover, we formulate an intermediate maximality principle, which is shown here to be equiconsistent with the existence of a weakly compact cardinal $kappa$ such that $V_{kappa}prec V$.Mon, 20 Feb 2017 20:30:00 +0100Further inequalities for operator space numerical radius on 2*2 operator matrices
http://bims.iranjournals.ir/article_1022_0.html
‎We present some inequalities for operator space numerical radius of $2times 2$ block matrices on the matrix space $mathcal{M}_n(X)$‎, ‎when $X$ is a numerical radius operator space‎. ‎These inequalities contain some upper and lower bounds for operator space numerical radius.Mon, 20 Feb 2017 20:30:00 +0100Application of frames in Chebyshev and conjugate gradient methods
http://bims.iranjournals.ir/article_1023_0.html
‎Given a frame of a separable Hilbert space $H$‎, ‎we present some‎ ‎iterative methods for solving an operator equation $Lu=f$‎, ‎where $L$ is a bounded‎, ‎invertible and symmetric‎ ‎operator on $H$‎. ‎We present some algorithms ‎based on the knowledge of frame bounds‎, ‎Chebyshev method and conjugate gradient method‎, ‎in order to give some‎ ‎approximated solutions to the problem‎. ‎Then we investigate the‎ ‎convergence and optimality of them.Mon, 20 Feb 2017 20:30:00 +0100Stochastic evolution equations with multiplicative Poisson noise and monotone nonlinearity
http://bims.iranjournals.ir/article_1024_0.html
Semilinear stochastic evolution equations with multiplicative Poisson noise and monotone nonlinear drift in Hilbert spaces are considered. The coefficients are assumed to have linear growth. We do not impose coercivity conditions on coefficients. A novel method of proof for establishing existence and uniqueness of the mild solution is proposed. Examples on stochastic partial differential equations and stochastic delay differential equations are provided to demonstrate the theory developed.Mon, 20 Feb 2017 20:30:00 +0100Improvements of Young inequality using the Kantorovich constant
http://bims.iranjournals.ir/article_1025_0.html
‎Some improvements of Young inequality and its reverse‎‎for positive numbers with Kontrovich constant $K(t‎, ‎2)=frac{(1+t)^2}{4t}$ are given‎. ‎Using these inequalities some operator inequalities and Hilbert-Schmidt norm versions for matrices are proved‎. ‎In particular‎, ‎it is shown that if $a‎, ‎b$ are positive numbers and $0 leqslant nu leqslant 1,$ then for all integers $ kgeqslant 1‎: ‎$‎‎begin{align*}‎ ‎K(h^{frac{1}{2^n}},2)^{r_n} asharp_{nu}b &leqslant anabla_{nu} b‎ -‎sum_{k=0}^{n-1}r_{k}left((a sharp_{frac{m_k}{2^k}} b‎‎)^{frac{1}{2}}‎- ‎(a sharp_{frac{m_k+1}{2^k}}b‎‎)^{frac{1}{2}}right)^{2}‎ ‎&leqslant K(h^{frac{1}{2^n}},2)^{R_n} asharp_{nu}b,‎end{align*}‎‎where $m_k=‎ [‎2^knu ] $ is the largest integer not greater than‎ ‎$2^knu$‎, ‎$ r_0=min {nu‎,‎1-nu}‎, ‎$ $ r_{k}=min { 2r_{k-1}‎, ‎1-2r_{k-1} } $ and $R_k=1-r_k$‎.Mon, 20 Feb 2017 20:30:00 +0100Dilations for $C^ast$-dynamical systems with abelian groups on Hilbert $C^ast$-modules
http://bims.iranjournals.ir/article_1026_0.html
In this paper we investigate the dilations of completely positive definite representations of $C^ast$-dynamical systems with abelian groups on Hilbert $C^ast$-modules. We show that if $(mathcal{A}, G,alpha)$ is a $C^ast$-dynamical system with $G$ an abelian group, then every completely positive definite covariant representation $(pi,varphi,E)$ of $(mathcal{A}, G,alpha)$on a Hilbert $C^ast$-module $E$ admits an unitary dilation $(hat{pi},hat{varphi},hat{E})$.Mon, 20 Feb 2017 20:30:00 +0100Some topologies on the space of quasi-multipliers
http://bims.iranjournals.ir/article_1027_0.html
‎Assume that $A$ is a Banach algebra. We define‎ ‎$beta-$topology and $gamma-$topology on the space $QM_{el}(A^{*})$ of all bounded extended left quasi-multipliers of $A^{*}.$‎ ‎We establish further properties of $(QM_{el}(A^{*}),gamma)$ when $A$ is a $C^{*}-$algebra‎. ‎In particular‎, ‎we characterize the $gamma-$dual‎ ‎of $QM_{el}(A^{*})$ and prove that $(QM_{el}(A^{*}),gamma)^{*},$ under the topology of bounded convergence‎, ‎is isomorphic to $A^{***}.Mon, 20 Feb 2017 20:30:00 +0100Strongly nil-clean corner rings
http://bims.iranjournals.ir/article_1028_0.html
We show that if $R$ is a ring with an arbitrary idempotent $e$ such that $eRe$ and $(1-e)R(1-e)$ are both strongly nil-clean rings‎, ‎then $R/J(R)$ is nil-clean‎. ‎In particular‎, ‎under certain additional circumstances‎, ‎$R$ is also nil-clean‎. ‎These results somewhat improves on achievements due to Diesl in J‎. ‎Algebra (2013) and to Koc{s}an-Wang-Zhou in J‎. ‎Pure Appl‎. ‎Algebra (2016)‎. ‎In addition‎, ‎we also give a new transparent proof of the main result of Breaz-Calugareanu-Danchev-Micu in Linear Algebra Appl‎. ‎(2013) which says that if $R$ is a commutative nil-clean ring‎, ‎then the full $ntimes n$ matrix ring $mathbb{M}_n(R)$ is nil-clean‎.Mon, 20 Feb 2017 20:30:00 +0100Inverse Sturm--Liouville problems using three spectra with finite number of transmission and ...
http://bims.iranjournals.ir/article_1029_0.html
‎In this manuscript‎, ‎we study various by uniqueness results for inverse spectral problems of Sturm--Liouville operators using three spectrum with a finite number of discontinuities at interior points which we impose the usual transmission conditions‎. ‎We consider both the cases of classical Robin and eigenparameter dependent boundary conditions.Mon, 20 Feb 2017 20:30:00 +0100onvergence of the sinc method applied to delay Volterra integral equations
http://bims.iranjournals.ir/article_1030_0.html
‎In this paper‎, ‎the numerical solutions of linear and nonlinear Volterra integral‎ ‎equations with nonvanishing delay are considered by two methods‎. ‎The methods are developed by means of‎ ‎the sinc approximation with the single exponential (SE) and double exponential (DE)‎ ‎transformations‎. ‎The existence and uniqueness of sinc-collocation solutions for these equations are provided‎. ‎These methods improve conventional results and achieve exponential convergence‎. ‎Numerical results are included to confirm the efficiency and accuracy of the methods.Mon, 20 Feb 2017 20:30:00 +0100A stochastic version analysis of an M/G/1 retrial queue with Bernoulli schedule
http://bims.iranjournals.ir/article_1031_0.html
In this work, we derive insensitive bounds for various performance measures of a single-server retrial queue with generally distributed inter-retrial times and Bernoulli schedule, under the special assumption that only the customer at the head of the orbit queue (i.e., a FCFS discipline governing the flow from the orbit to the server) is allowed to occupy the server. The methodology is strongly based on stochastic comparison techniques. Instead of studying a performance measure in a quantitative fashion, this approach attempts to reveal the relationship between the performance measures and the parameters of the system. We prove the monotonicity of the transition operator of the embedded Markov chain relative to strong stochastic ordering and increasing convex ordering. We obtain comparability conditions for the distribution of the number of customers in the system. Bounds are derived for the stationary distribution and some simple bounds for the mean characteristics of the system. The proofs of these results are based on the validation of some inequalities for some cumulative probabilities associated with every state (m, n) of the system. Finally, the effects of various parameters on the performance of the system have been examined numerically.Mon, 20 Feb 2017 20:30:00 +0100An algorithm for approximating nondominated points of convex multiobjective optimization problems
http://bims.iranjournals.ir/article_1032_0.html
‎In this paper‎, ‎we present an algorithm for generating approximate nondominated points of a multiobjective optimization problem (MOP)‎, ‎where the constraints and the objective functions are convex‎. ‎We provide outer and inner approximations of nondominated points and prove that inner approximations provide a set of approximate weakly nondominated points‎. ‎The proposed algorithm can be applied for differentiable or nondifferentiable convex MOPs‎. ‎To illustrate efficiency of the proposed algorithm for convex MOPs‎, ‎we provide numerical examples.Mon, 20 Feb 2017 20:30:00 +0100Complete pivoting strategy for the $IUL$ preconditioner obtained from Backward Factored ...
http://bims.iranjournals.ir/article_1033_0.html
‎In this paper‎, ‎we use a complete pivoting strategy to compute the $IUL$ preconditioner obtained as the by-product of the Backward Factored APproximate INVerse process‎. ‎This pivoting is based on the complete pivoting strategy of the Backward $IJK$ version of Gaussian Elimination process‎. ‎There is a parameter $alpha$ to control the complete pivoting process‎. ‎We have studied the effect of different values of $alpha$ on the quality of the $IUL$ preconditioner‎. ‎For the numerical experiments section‎, ‎the $IUL$ factorization which is coupled with the complete pivoting is compared to the $ILUTP$ and to the left-looking version of $RIF$ which is coupled with the complete pivoting strategy‎. ‎As the preprocessing‎, ‎we have applied the maximum weighted matching coupled the Reverse Cuthill-Mckee ($RCM$) and multilevel nested dissection reordering.Mon, 20 Feb 2017 20:30:00 +0100Caratheodory dimension for observers
http://bims.iranjournals.ir/article_1034_0.html
‎In this essay we introduce and study the notion of dimension for observers via Caratheodory structures and relative probability measures‎. ‎We show that the dimension as a three variables function is an increasing function on observers‎, ‎and decreasing function on the cuts of an observer‎. ‎We find observers with arbitrary non-negative dimensions‎. ‎We show that Caratheodory dimension for observers is an invariant object under conjugate relations‎. ‎Caratheodory dimension as a mapping‎, ‎for multi-dimensional observers is considered‎. ‎News spread is modeled via multi-dimensional observers‎.Mon, 20 Feb 2017 20:30:00 +0100Functional identities of degree 2 in CSL algebras
http://bims.iranjournals.ir/article_1035_0.html
‎Let $mathscr{L}$ be a commutative subspace lattice generated by finite many commuting independent nests on a complex separable Hilbert space $mathbf{H}$ with ${rm dim}hspace{2pt}mathbf{H}geq 3$‎, ‎${rm Alg}mathscr{L}$‎ ‎the CSL algebra associated with $mathscr{L}$ and $mathscr{M}$ be an algebra containing ${rm Alg}mathscr{L}$‎. ‎This article is aimed at describing the form of‎ ‎additive mapppings $F_1‎, ‎F_2‎, ‎G_1‎, ‎G_2colon {rm Alg}mathscr{L}longrightarrow mathscr{M}$ satisfying functional identity‎ ‎$F_1(X)Y+F_2(Y)X+XG_2(Y)+YG_1(X)=0$ for all $X‎, ‎Yin {rm Alg}mathscr{L}$‎. ‎As an application generalized inner biderivations and commuting‎ ‎additive mappings are determined‎.Mon, 20 Feb 2017 20:30:00 +0100On a p-Laplacian system and a generalization of the Landesman-Lazer type condition
http://bims.iranjournals.ir/article_1036_0.html
This article shows the existence of weak solutions of a resonance problem for nonuniformly p-Laplacian system in a bounded domain in $mathbb{R}^N$‎. ‎Our arguments are based on the minimum principle and rely on a generalization of the Landesman-Lazer type condition‎.Mon, 20 Feb 2017 20:30:00 +0100Some rank equalities for finitely many tripotent matrices
http://bims.iranjournals.ir/article_1037_0.html
It is established a rank equality for the sum of finitely many tripotent matrices via elementary block matrix operations. Moreover, by using this equality and Theorems 8 and 10 in [Chen M. and et al. On the open problem related to rank equalities for the sum of finitely many idempotent matrices and its applications, The Scientific World Journal, 2014], it is given some other rank equalities for tripotent matrices. Furthermore, it is obtained several rank equalities related to some special types of matrices, some of which are available in the literature, from the results established.Mon, 20 Feb 2017 20:30:00 +0100Decay estimates of solutions to the IBq equation
http://bims.iranjournals.ir/article_1038_0.html
‎In this paper we focus on the Cauchy problem for the generalized‎ ‎IBq equation with damped term in $n$-dimensional space‎. ‎We establish the global existence and decay estimates of solution with $L^q(1leq qleq 2)$ initial value‎, ‎provided that the initial value is suitably small‎. ‎Moreover‎, ‎we also show that the solution is asymptotic to the solution $u_L$ to the corresponding linear equation as time tends to infinity‎. ‎Finally‎, ‎asymptotic profile of the solution $u_L$ to the linearized problem is also discussed‎.Mon, 20 Feb 2017 20:30:00 +0100Analogues of some determinantal inequalities for sector matrices
http://bims.iranjournals.ir/article_1039_0.html
In this note, some analogues of classic determinantal inequalities are presented for sector matrices, such as the Minkowski inequality, Fischer's inequality etc.Mon, 20 Feb 2017 20:30:00 +0100On three-dimensional $N(k)$-paracontact metric manifolds and Ricci solitons
http://bims.iranjournals.ir/article_1040_0.html
The aim of this paper is to characterize $3$-dimensional $N(k)$-paracontact metric manifolds satisfying certain curvature conditions. We prove that a $3$-dimensional $N(k)$-paracontact metric manifold $M$ admits a Ricci soliton whose potential vector field is the Reeb vector field $xi$ if and only if the manifold is a paraSasaki-Einstein manifold. Several consequences of this result are discussed. Finally, an illustrative example is constructed.Mon, 20 Feb 2017 20:30:00 +0100Very cleanness of generalized matrices
http://bims.iranjournals.ir/article_1041_0.html
An element $a$ in a ring $R$ is very clean in case there exists‎ ‎an idempotent $ein R$ such that $ae = ea$ and either $a‎- ‎e$ or $a‎ + ‎e$ is invertible‎. ‎An element $a$ in a ring $R$ is very $J$-clean‎ ‎provided that there exists an idempotent $ein R$ such that $ae =‎‎ea$ and either $a-ein J(R)$ or $a‎ + ‎ein J(R)$‎. ‎Let $R$ be a‎ ‎local ring‎, ‎and let $sin C(R)$‎. ‎We prove that $Ain K_s(R)$ is‎ ‎very clean if and only if $Ain U(K_s(R))$; $Ipm Ain U(K_s(R))$‎ ‎or $Ain K_s(R)$ is very J-clean‎.Mon, 20 Feb 2017 20:30:00 +0100The length of Artinian modules with countable Noetherian dimension
http://bims.iranjournals.ir/article_1042_0.html
‎It is shown that‎ ‎if $M$ is an Artinian module over a ring‎ ‎$R$‎, ‎then $M$ has Noetherian dimension $alpha $‎, ‎where $alpha $ is a countable ordinal number‎, ‎if and only if $omega ^{alpha }+2leq it{l}(M)leq omega ^{alpha‎ +1}$, ‎where $ it{l}(M)$ is‎ ‎the length of $M$‎, ‎$i.e.,$ the least ordinal number such that the interval $[0‎, ‎ it{l}(M))$ cannot be embedded in the lattice of all submodules of $M$.Mon, 20 Feb 2017 20:30:00 +0100Jordan derivations and Lie derivations on path algebras
http://bims.iranjournals.ir/article_1043_0.html
‎Without the faithful assumption‎, ‎we prove that every Jordan‎ ‎derivation on a class of path algebras of quivers without oriented‎ ‎cycles is a derivation and that every Lie derivation on such kinds‎ ‎of algebras is of the standard form.Mon, 20 Feb 2017 20:30:00 +0100On derivations and biderivations of trivial extensions and triangular matrix rings
http://bims.iranjournals.ir/article_1044_0.html
‎Triangular matrix rings are examples of trivial extensions‎. ‎In this article we determine the structure of derivations and biderivations of the trivial extensions‎, ‎and thereby we describe the derivations and biderivations of the upper triangular matrix rings‎. ‎Some related results are also obtained‎.Mon, 20 Feb 2017 20:30:00 +0100Two-geodesic transitive graphs of prime power order
http://bims.iranjournals.ir/article_1045_0.html
In a non-complete graph $Gamma$, a vertex triple $(u,v,w)$ with $v$ adjacent to both $u$ and $w$ is called a $2$-geodesic if $uneq w$ and $u,w$ are not adjacent. The graph $Gamma$ is said to be $2$-geodesic transitive if its automorphism group is transitive on arcs, and also on 2-geodesics. We first produce a reduction theorem for the family of $2$-geodesic transitive graphs of prime power order. Next, we classify such graphs which are also vertex quasiprimitive.Mon, 20 Feb 2017 20:30:00 +0100Convex combinations of harmonic shears of slit mappings
http://bims.iranjournals.ir/article_1046_0.html
In this paper, we study the linear combinations of harmonic mappings obtained by shearing a class of slit conformal mappings. Sufficient conditions for the linear combinations of harmonic mappings of this family to be univalent and convex in the horizontal direction are derived. Several examples of univalent harmonic mappings constructed by using these methods are presented to illustrate potential applications of the main results.Mon, 20 Feb 2017 20:30:00 +0100A simple proof of Zariski's Lemma
http://bims.iranjournals.ir/article_1047_0.html
‎Our aim in this very short note is to show that the proof of the‎ ‎following well-known fundamental lemma of Zariski follows from an‎ ‎argument similar to the proof of the fact that the rational field‎ ‎$mathbb{Q}$ is not a finitely generated $mathbb{Z}$-algebra.Mon, 20 Feb 2017 20:30:00 +0100Weak convergence of splitting algorithms in Hilbert spaces with their applications
http://bims.iranjournals.ir/article_1048_0.html
‎In this article‎, ‎we study the convergence of a splitting algorithm‎ ‎for solving a convex feasibility problem‎. ‎Weak convergence of the purposed algorithm is obtained in the framework of real Hilbert spaces‎. ‎Applications are also provided to support the main results.Mon, 20 Feb 2017 20:30:00 +0100Stability of F-biharmonic maps
http://bims.iranjournals.ir/article_1049_0.html
This paper studies some properties of F-biharmonic maps between Riemannian manifolds. By considering the first variation formula of the F-bienergy functional, F-biharmonicity of conformal maps are investigated. Moreover, the second variation formula for F-biharmonic maps is obtained. As an application, instability and nonexistence theorems for F-biharmonic maps are given.Mon, 20 Feb 2017 20:30:00 +0100Measure of non strict singularity of Schechter essential spectrum of two bounded operators and ...
http://bims.iranjournals.ir/article_1050_0.html
In this paper, we discuss the essential spectrum of the sum of two bounded operators by means of measure of non strict singularity. As application, based on this new investigation, a problem of one-speed neutron transport operator is presented.Mon, 20 Feb 2017 20:30:00 +0100Extension functors of Cousin cohomology modules
http://bims.iranjournals.ir/article_1051_0.html
‎‎‎Let $R$ be a commutative Noetherian ring with non-zero identity‎, ‎$mathcal{F}$ a filtration of $Spec(R)$ which admits an $R$--module $X$‎, ‎and $Co_R(mathcal{F},X)$ the Cousin complex for $X$ with respect to $mathcal{F}$‎. ‎In this paper‎, ‎we first introduce the Cousin functor and the Cousin spectral sequences‎. ‎Then for non-negative integers $s‎, ‎t$ and a finite $R$--module $N$‎, ‎we study the membership of $R$--modules $h^{s-1}(Ext^t_R(N,Co_R(mathcal{F},X)))$ and $Ext^{s}_R(N,h^{t-1}(Co_R(mathcal{F},X)))$ in Serre subcategories of the category of $R$--modules and find some conditions for validity of an isomorphism between them‎. ‎Finally‎, ‎we use these results to present some facts about the vanishing and finiteness of Cousin cohomology modules.Mon, 20 Feb 2017 20:30:00 +0100Gorenstein hereditary rings with respect to a semidualizing module
http://bims.iranjournals.ir/article_1052_0.html
Let $C$ be a semidualizing module. We first investigate the properties of finitely generated $G_C$-projective modules.Then, relative to $C$, we introduce and study the rings over which every submodule of a projective (flat) module is $G_C$-projective (flat), which we call $C$-Gorenstein (semi)hereditary rings. It is proved that every $C$-Gorenstein hereditary ring is both coherent and $C$-Gorenstein semihereditary.Mon, 27 Feb 2017 20:30:00 +0100Duality for vector equilibrium problems with constraints
http://bims.iranjournals.ir/article_1053_0.html
In the paper, we study duality for vector equilibrium problems using a concept of generalized convexity in dealing with the quasi-relative interior. Then, their applications to optimality conditions for quasi-relative efficient solutions are obtained. Our results are extensions of several existing ones in the literature when the ordering cones in both the objective space and the constraint space have possibly empty interior.Mon, 27 Feb 2017 20:30:00 +0100An upper bound for the regularity of powers of edge ideals
http://bims.iranjournals.ir/article_1054_0.html
‎A recent result due to H`{a} and Van Tuyl proved that the Castelnuovo-Mumford regularity of the quotient ring $R/I(G)$ is at most matching number of $G$‎, ‎denoted by ${rm match}(G)$‎. ‎In this paper‎, ‎we provide a generalization of this result for powers of edge ideals‎. ‎More precisely‎, ‎we show that for every graph $G$ and every $sgeq 1$‎, ‎$${rm reg}(R‎/ ‎I(G)^{s})leq (2s-1) |E(G)|^{s-1} {rm match}(G).$$Mon, 27 Feb 2017 20:30:00 +0100Five-value rich lines, Borel directions and uniqueness of meromorphic functions
http://bims.iranjournals.ir/article_1055_0.html
For a meromorphic function $f$ in the complex plane, we shall introduce the definition of five-value rich line of $f$, and study the uniqueness of meromorphic functions of finite order in an angular domain by involving the five-value rich line and Borel directions. Finally, the relationship between a five-value rich line and a Borel direction is discussed, that is, every Borel direction of $f$ is its five-value rich line, and the inverse statement holds when $f$ is of infinite order.Mon, 27 Feb 2017 20:30:00 +0100Properties of matrices with numerical ranges in a sector
http://bims.iranjournals.ir/article_1056_0.html
Let $(A)$ be a complex $(ntimes n)$ matrix and assume that the numerical range of $(A)$ lies in the set of a sector of half angle $(alpha)$ denoted by $(S_{alpha})$. We prove the numerical ranges of the conjugate, inverse and Schur complement of any order of $(A)$ are in the same $(S_{alpha})$.The eigenvalues of some kinds of matrix product and numerical ranges of hadmard product, star-congruent matrix and unitary matrix of polar decompostion are also included in the same sector. Furthermore, we extend some inequalities about eigenvalues and singular values and the linear fractional maps to this class of matrices.Mon, 27 Feb 2017 20:30:00 +0100On nuclei of sup-$\Sigma$-algebras
http://bims.iranjournals.ir/article_1057_0.html
In this paper, algebraic investigations on sup-$Sigma$-algebras are presented. A representation theorem for sup-$Sigma$-algebras in terms of nuclei and quotients is obtained. Consequently, the relationship between the congruence lattice of a sup-$Sigma$-algebra and the lattice of its nuclei is fully developed.Mon, 27 Feb 2017 20:30:00 +0100NSE characterization of some linear groups
http://bims.iranjournals.ir/article_1058_0.html
For a finite group $G$‎, ‎let $nse(G)={m_kmid kinpi_e(G)}$‎, ‎where $m_k$ is the number of elements of order $k$ in $G$‎‎and $pi_{e}(G)$ is the set of element orders of $G$‎. ‎In this paper‎, ‎we prove that $Gcong L_m(2)$ if and only if $pmid |G|$ and $nse(G)=nse(L_m(2))$‎, ‎where $min {n,n+1}$ and $2^n-1=p$ is a prime number‎.Mon, 27 Feb 2017 20:30:00 +0100High-accuracy alternating segment explicit-implicit method for the fourth-order heat equation
http://bims.iranjournals.ir/article_1059_0.html
Based on a group of new Saul’yev type asymmetric difference schemes constructed by author, a high-order, unconditionally stable and parallel alternating segment explicit-implicit method for the numerical solution of the fourth-order heat equation is derived in this paper. The truncation error is fourth-order in space, which is much more accurate than the known alternating segment explicit-implicit methods. Numerical simulations are performed to show the effectiveness of thepresent method that are in preference to the prior methods.Mon, 27 Feb 2017 20:30:00 +0100Applications of convolution and subordination to certain $p$-valent functions
http://bims.iranjournals.ir/article_1060_0.html
In this paper we considered some new classes of multivalent functions by using Aouf-Silverman-Srivastava operator and derived some important results using convolution and subordination technique. This new class is an extension of a class which introduced before.Mon, 27 Feb 2017 20:30:00 +0100The graph of equivalence classes and Isoclinism of groups
http://bims.iranjournals.ir/article_1061_0.html
‎Let $G$ be a non-abelian group and let $Gamma(G)$ be the non-commuting graph of $G$‎. ‎In this paper we define an equivalence relation $sim$ on the set of $V(Gamma(G))=Gsetminus Z(G)$ by taking $xsim y$ if and only if $N(x)=N(y)$‎, ‎where $ N(x)={uin G | x textrm{ and } u textrm{ are adjacent in }Gamma(G)}$ is the open neighborhood of $x$ in $Gamma(G)$‎. ‎We introduce a new graph determined by equivalence classes of non-central elements of $G$‎, ‎denoted $Gamma_E(G)$‎, ‎as the graph whose vertices are ${[x] | x in Gsetminus Z(G)}$ and join two distinct vertices $[x]$ and $[y]$‎, ‎whenever $[x,y]neq 1$‎. ‎We prove that group $G$ is AC-group if and only if $Gamma_E(G)$ is complete graph‎. ‎Among other results‎, ‎we show that the graphs of equivalence classes of non-commuting graph associated with two isoclinic groups are isomorphic.Mon, 27 Feb 2017 20:30:00 +0100Hyperbolic surfaces of $L_1$-2-type
http://bims.iranjournals.ir/article_1062_0.html
In this paper, we show that an $L_1$-2-type surface in the three-dimensional hyperbolic space $H^3subset R^4_1$ either is an open piece of a standard Riemannian product $ H^1(-sqrt{1+r^2})times S^{1}(r)$, or it has non constant mean curvature, non constant Gaussian curvature, and non constant principal curvatures.Mon, 27 Feb 2017 20:30:00 +0100The second dual of strongly zero-product preserving maps
http://bims.iranjournals.ir/article_1063_0.html
The notion of strongly Lie zero-product preserving maps on normed algebras as a generalization of Lie zero-product preserving maps are dened. We give a necessary and sufficient condition from which a linear map between normed algebras to be strongly Lie zero-product preserving. Also some hereditary properties of strongly Lie zero-product preserving maps are presented. Finally the second dual of a strongly zero-product, strongly Jordan zero-product and strongly Lie zero-product preserving map on a certain class of normed algebras are investigated.Mon, 27 Feb 2017 20:30:00 +0100Classification of solvable groups with a given property
http://bims.iranjournals.ir/article_1064_0.html
In this paper we classify all finite solvable groups satisfying the following property P5: their orders of representatives are set-wise relatively prime for any 5 distinct non-central conjugacy classes.Mon, 27 Feb 2017 20:30:00 +0100Holder continuity of solution maps to a parametric weak vector equilibrium problem
http://bims.iranjournals.ir/article_1065_0.html
In this paper, by using a new concept of strong convexity, we obtain sufficient conditions for Holder continuity of the solution mapping for a parametric weak vector equilibrium problem in the case where the solution mapping is a general set-valued one. Without strong monotonicity assumptions, the Holder continuity for solution maps to parametric weak vector optimization problems is discussed.Mon, 27 Feb 2017 20:30:00 +0100Defining relations of a group $\Gamma= G^{3,4}(2,Z)$ and its action on real quadratic field
http://bims.iranjournals.ir/article_1066_0.html
In this paper‎, ‎we have shown that the coset diagrams for the‎ ‎action of a linear-fractional group $Gamma$ generated by the linear-fractional‎ ‎transformations $r:zrightarrow frac{z-1}{z}$ and $s:zrightarrow frac{-1}{2(z+1)}$ on‎ ‎the rational projective line is connected and transitive‎. ‎By using coset diagrams‎, ‎we have shown that $r^{3}=s^{4}=1$ are defining relations for $Gamma$‎. ‎Furthermore‎, ‎we have studied some important results for the action of group $Gamma$ on real‎ ‎quadratic field $Q(sqrt{n})$‎. ‎Also‎, ‎we have classified all the ambiguous numbers in the orbit.Mon, 27 Feb 2017 20:30:00 +0100Entropy of a semigroup of maps from a set-valued view
http://bims.iranjournals.ir/article_1067_0.html
In this paper, we introduce a new entropy-like invariant, named Hausdorff metric entropy, for finitely generated semigroups acting on compact metric spaces from a set-valued view and study its properties. We establish the relation between Hausdorff metric entropy and topological entropy of a semigroup defined by Bis. Some examples with positive or zero Hausdorff metric entropy are given. Moreover, some notions of chaos are also well generalized for finitely generated semigroups from a set-valued view.Mon, 27 Feb 2017 20:30:00 +0100Initial coefficients of starlike functions with real coefficients
http://bims.iranjournals.ir/article_1068_0.html
The sharp bounds for the third and fourth coefficients of Ma-Minda starlike functions having fixed second coefficient are determined. These results are proved by using certain constraint coefficient problem for functions with positive real part whose coefficients are real and the first coefficient is kept fixed. Analogous results are obtained for a general class of close-to-convex functionsMon, 27 Feb 2017 20:30:00 +0100Classifying pentavalnet symmetric graphs of order $24p$
http://bims.iranjournals.ir/article_1069_0.html
A graph is said to be symmetric if its automorphism group is transitive on its arcs. A complete classification is given of pentavalent symmetric graphs of order 24p for each prime p. It is shown that a connected pentavalent symmetric graph of order 24p exists if and only if p=2, 3, 5, 11 or 17, and up to isomorphism, there are only eleven such graphs.Mon, 27 Feb 2017 20:30:00 +0100Existence of positive solutions for a second-order p-Laplacian impulsive boundary value problem ...
http://bims.iranjournals.ir/article_1070_0.html
In this paper, we investigate the existence of positive solutions for a second-order multipoint p-Laplacian impulsive boundary value problem on time scales. Using a new fixed point theorem in a cone, sufficient conditions for the existence of at least three positive solutions are established. An illustrative example is also presented.Sun, 12 Mar 2017 20:30:00 +0100Faber polynomial coefficient estimates for bi-univalent functions defined by the Tremblay ...
http://bims.iranjournals.ir/article_1071_0.html
Using the Tremblay fractional derivative operator in the complex domain, we introduce and investigate a new class of analytic and bi-univalent functions in the open unit disk. We use the Faber polynomial expansions to obtain upper boundsfor the general coefficients of such functions subject to a gap series condition as well as obtaining bounds for their first two coefficients.Sun, 12 Mar 2017 20:30:00 +0100n-Array Jacobson graphs
http://bims.iranjournals.ir/article_1072_0.html
We generalize the notion of Jacobson graphs into $n$-array columns called $n$-array Jacobson graphs and determine their connectivities and diameters. Also, we will study forbidden structures of these graphs and determine when an $n$-array Jacobson graph is planar, outer planar, projective, perfect or domination perfect.Sun, 12 Mar 2017 20:30:00 +0100When is the ring of real measurable functions a hereditary ring?
http://bims.iranjournals.ir/article_1073_0.html
‎Let $M(X‎, ‎mathcal{A}‎, ‎mu)$ be the ring of real-valued measurable functions‎ ‎on a measure space $(X‎, ‎mathcal{A}‎, ‎mu)$‎. ‎In this paper‎, ‎we characterize the maximal ideals in the rings of real measurable functions‎ ‎and as a consequence‎, ‎we determine when $M(X‎, ‎mathcal{A}‎, ‎mu)$ is a hereditary ring.Sun, 12 Mar 2017 20:30:00 +0100Subdirectly irreducible acts over some semigroups
http://bims.iranjournals.ir/article_1074_0.html
‎In this paper‎, ‎we characterize and find the number of subdirectly‎ ‎irreducible acts over some classes of semigroups‎, ‎such as zero‎ ‎semigroups‎, ‎right zero semigroups‎ ‎and strong chain of left zero semigroups.Sun, 12 Mar 2017 20:30:00 +0100The lower bound for the number of 1-factors in generalized Petersen graphs
http://bims.iranjournals.ir/article_1075_0.html
‎In this paper‎, ‎we investigate the number of 1-factors of a‎ ‎generalized Petersen graph $P(N,k)$ and get a lower bound for the‎ ‎number of 1-factors of $P(N,k)$ as $k$ is odd‎, ‎which shows that the‎ ‎number of 1-factors of $P(N,k)$ is exponential in this case and‎ ‎confirms a conjecture due to Lov'{a}sz and Plummer (Ann‎. ‎New York Acad‎. ‎Sci‎. ‎576(2006)‎, ‎no‎. ‎1‎, ‎389-398).Sun, 12 Mar 2017 20:30:00 +0100Composition of resolvents and quasi-nonexpansive multivalued mappings in Hadamared spaces
http://bims.iranjournals.ir/article_1076_0.html
‎The proximal point algorithm‎, ‎which is a well-known tool for finding‎ ‎minima of convex functions‎, ‎is generalized from the classical‎ ‎Hilbert space framework into a nonlinear setting‎, ‎namely‎, ‎geodesic‎ ‎metric spaces of nonpositive curvature‎. ‎In this paper we propose an‎ ‎iterative algorithm for finding the common element of the‎ ‎minimizers of a finite family of convex functions and the common ‎fixed points of a finite family of quasi-nonexpansive multivalued‎ ‎mappings in Hadamard‎ ‎spaces.Sun, 12 Mar 2017 20:30:00 +0100A hybrid mean value involving a new Gauss sums and Dedekind sums
http://bims.iranjournals.ir/article_1077_0.html
‎In this paper‎, ‎we introduce a new sum‎ ‎analogous to Gauss sum‎, ‎then we use the properties of the‎ ‎classical Gauss sums and analytic method to study the hybrid mean‎ ‎value problem involving this new sums and Dedekind sums‎, ‎and‎ ‎give an interesting identity for it.Sun, 12 Mar 2017 20:30:00 +0100Semi-Rothberger and related spaces
http://bims.iranjournals.ir/article_1078_0.html
In this paper our focus is to study certain covering properties in topological spaces by using semi-open covers. A part of this article deals with Rothberger-type covering properties. The notions of s-Rothberger, almost s-Rothberger, star s-Rothberger, almost star s-Rothberger, strongly star s-Rothberger spaces are defined and corresponding properties are investigated.Sun, 12 Mar 2017 20:30:00 +0100A descent method for explicit computations on curves
http://bims.iranjournals.ir/article_1079_0.html
‎It is shown that the knowledge of a surjective morphism $Xto Y$ of complex‎ ‎curves can be effectively used‎ ‎to make explicit calculations‎. ‎The method is demonstrated‎ ‎by the calculation of $j(ntau)$ (for some small $n$) in terms of $j(tau)$ for the elliptic curve ‎with period lattice $(1,tau)$‎, ‎the period matrix for the Jacobian of a family of genus-$2$ curves‎ ‎complementing the classic calculations of Bolza‎ ‎and explicit general formulae for branched covers of an elliptic curve with exactly one ramification point.Sun, 12 Mar 2017 20:30:00 +0100Upper bounds for noetherian dimension of all injective modules with Krull dimension
http://bims.iranjournals.ir/article_1080_0.html
‎In this paper we give an upper bound for Noetherian dimension of all injective modules with Krull dimension on arbitrary rings‎. ‎In particular‎, ‎we also give an upper bound for Noetherian dimension of all Artinian modules on Noetherian duo rings.Sun, 12 Mar 2017 20:30:00 +0100Locally finite basic classical simple Lie superalgebras
http://bims.iranjournals.ir/article_1081_0.html
In this work, we study direct limits of finite dimensional basic classical simple Lie superalgebras and obtain the conjugacy classes of Cartan subalgebras under the group of automorphisms.Sun, 12 Mar 2017 20:30:00 +0100On normalizers of maximal subfields of division algebras
http://bims.iranjournals.ir/article_1082_0.html
‎Here‎, ‎we investigate a conjecture posed by Amiri and Ariannejad claiming‎ ‎that if every maximal subfield of a division ring $D$ has trivial normalizer‎, ‎then $D$ is commutative‎. ‎Using Amitsur classification of‎ ‎finite subgroups of division rings‎, ‎it is essentially shown that if‎ ‎$D$ is finite dimensional over its center then it contains a maximal‎ ‎subfield with non-trivial normalizer if and only if $D^*$ contains a‎ ‎non-abelian soluble subgroup‎. ‎This result generalizes a theorem of‎ ‎Mahdavi-Hezavehi and Tignol about cyclicity of division algebras of prime index.Sun, 12 Mar 2017 20:30:00 +0100Singular values of convex functions of matrices
http://bims.iranjournals.ir/article_1083_0.html
‎Let $A_{i},B_{i},X_{i},i=1,dots,m,$ be $n$-by-$n$ matrices such that $‎sum_{i=1}^{m}leftvert A_{i}rightvert ^{2}$ and $‎sum_{i=1}^{m}leftvert B_{i}rightvert ^{2}$ are nonzero matrices and each $X_{i}$ is‎ ‎positive semidefinite‎. ‎It is shown that if $f$ is a nonnegative increasing ‎convex function on $left[ 0,infty right) $ satisfying $fleft( 0right)‎ ‎=0 $‎, ‎then $$‎2s_{j}left( fleft( frac{leftvert sum_{i=1}^{m}A_{i}^{ast‎ ‎ }X_{i}B_{i}rightvert }{sqrt{leftVert sum_{i=1}^{m}leftvert‎ ‎ A_{i}rightvert ^{2}rightVert leftVert sum_{i=1}^{m}leftvert‎ ‎ B_{i}rightvert ^{2}rightVert }}right) right) leq s_{j}left( oplus‎ ‎_{i=1}^{m}fleft( 2X_{i}right) right)‎$$ ‎for $j=1,ldots,n$‎. ‎Applications of our results are given.Sun, 12 Mar 2017 20:30:00 +0100A new hybrid conjugate gradient algorithm for unconstrained optimization
http://bims.iranjournals.ir/article_1084_0.html
In this paper, a new hybrid conjugate gradient algorithm is proposed for solving unconstrained optimization problems. This new method can generate sufficient descent directions unrelated to any line search. Moreover, the global convergence of the proposed method is proved under the Wolfe line search. Numerical experiments are also presented to show the efficiency of the proposed algorithm, especially for solving highly dimensional problems.Sun, 12 Mar 2017 20:30:00 +0100Some results on pre-monotone operators
http://bims.iranjournals.ir/article_1085_0.html
‎In this paper‎, ‎some properties of pre-monotone operators are proved‎. ‎It is shown that in a reflexive Banach space‎, ‎a full domain multivalued $sigma$-monotone operator with sequentially norm$times$weak$^*$ closed graph is norm$times$weak$^*$ upper semicontinuous‎. ‎The notion of $sigma$-convexity is introduced and the‎ ‎relations between the $sigma$-monotonicity and $sigma$-convexity is investigated‎. ‎Moreover‎, ‎some results on the sum and difference of two $sigma$-monotone operators is considered.Sun, 12 Mar 2017 20:30:00 +0100Non-homogeneous continuous and discrete gradient systems: the quasi-convex case
http://bims.iranjournals.ir/article_1086_0.html
‎In this paper‎, ‎first we study the weak and strong convergence of solutions to the‎ ‎following first order nonhomogeneous gradient system‎ ‎$$begin{cases}-x'(t)=nablaphi(x(t))+f(t), text{a.e. on} (0,infty)\‎‎x(0)=x_0in Hend{cases}$$ to a critical point of $phi$‎, ‎where‎ ‎$phi$ is a $C^1$ quasi-convex function on a real Hilbert space‎ ‎$H$ with ${rm Argmin}phineqvarnothing$ and $fin L^1(0,+infty;H)$‎. ‎These results extend the‎ ‎results in the literature to non-homogeneous case‎. ‎Then the‎ ‎discrete version of the above system by backward Euler‎ ‎discretization has been studied‎. ‎Beside of the proof of the‎ ‎existence of the sequence given by the discrete system‎, ‎some‎‎results on‎ ‎the weak and strong convergence to the critical point of $phi$ are also proved‎. ‎These results when $phi$ is pseudo-convex (therefore the critical points‎ ‎are the same minimum points) may be applied in optimization for approximation of a‎ ‎minimum point of $phi$‎.Sun, 12 Mar 2017 20:30:00 +0100Inequalities for the polar derivative of a polynomial with $S$-fold zeros at the origin
http://bims.iranjournals.ir/article_1087_0.html
‎Let $p(z)$ be a polynomial of degree $n$ and for a complex number $alpha$‎, ‎let $D_{alpha}p(z)=np(z)+(alpha-z)p'(z)$ denote the polar derivative of the polynomial p(z) with respect to $alpha$‎. ‎Dewan et al proved‎ ‎that if $p(z)$ has all its zeros in $|z| leq k, (kleq‎ ‎1),$ with $s$-fold zeros at the origin then for every‎ ‎$alphainmathbb{C}$ with $|alpha|geq k$‎,
‎begin{align*}‎
‎max_{|z|=1}|D_{alpha}p(z)|geq‎
‎frac{(n+sk)(|alpha|-k)}{1+k}max_{|z|=1}|p(z)|‎.
‎end{align*} In this paper‎, ‎we obtain a refinement‎ ‎of above inequality‎. ‎Also as an application of our result‎, ‎we extend some inequalities for‎ ‎polar derivative of a polynomial of degree $n$ which‎ ‎does not vanish in $|z|< k$‎, ‎where $kgeq 1$‎, ‎except $s$-fold zeros at the origin‎. Sun, 12 Mar 2017 20:30:00 +0100On $\Phi$-$\tau$-quasinormal subgroups of finite groups
http://bims.iranjournals.ir/article_1088_0.html
‎Let $tau$ be a subgroup functor and $H$ a $p$-subgroup of a finite group $G$‎. ‎Let $bar{G}=G/H_{G}$ and $bar{H}=H/H_{G}$‎. ‎We say that $H$ is $Phi$-$tau$-quasinormal in $G$ if for some $S$-quasinormal subgroup $bar{T}$ of $bar{G}$ and some $tau$-subgroup $bar{S}$ of $bar{G}$ contained in $bar{H}$‎, ‎$bar{H}bar{T}$ is $S$-quasinormal in $bar{G}$ and $bar{H}capbar{T}leq bar{S}Phi(bar{H})$‎. ‎In this paper‎, ‎we study the structure of a group $G$ under the condition that some primary subgroups of $G$ are $Phi$-$tau$-quasinormal in $G$‎. ‎Some new characterizations about $p$-nilpotency and solubility of finite groups are obtained.Sun, 12 Mar 2017 20:30:00 +0100Nonlinear maps preserving product $X^{*}Y+Y^{*}X$ on von Neumann algebras
http://bims.iranjournals.ir/article_1089_0.html
‎Let $mathcal {A}$ and $mathcal {B}$ be two von Neumann algebras with no central abelian projections‎. ‎In this paper‎, ‎it is proved that if a not necessarily linear bijective map $Phi:mathcal {A}rightarrow mathcal {B}$ satisfies‎ ‎$Phi(A^{*}B+B^{*}A)=Phi(A)^{*}Phi(B)+Phi(B)^{*}Phi(A)$ for all‎ ‎$A‎, ‎Binmathcal {A}$‎, ‎then $Phi$ is a sum of a linear $*$-isomorphism and a conjugate‎ ‎linear $*$-isomorphism.Sun, 12 Mar 2017 20:30:00 +0100Zero elements and $z$-ideals in modified pointfree topology
http://bims.iranjournals.ir/article_1090_0.html
‎In this paper‎, ‎we define and study the notion of zero elements in topoframes; a topoframe is a pair‎ ‎$(L‎, ‎tau)$‎, ‎abbreviated $L_{ tau}$‎, ‎consisting of a frame $L$ and a‎ ‎subframe $ tau $ all of whose elements are complemented elements in‎ ‎$L$‎. ‎We show that‎ ‎the $f$-ring $ mathcal{R}(L_tau)$‎, ‎the set of $tau$-real continuous functions on $L$‎, ‎is uniformly complete‎. ‎Also‎, ‎the set of all zero elements in a topoframe‎ ‎is closed under the formation of countable meets and finite joins‎. ‎Also‎, ‎we introduce the notion of $z$-filters and $z$-ideals in modified pointfree topology‎ ‎and make ready some results about them‎. Sun, 12 Mar 2017 20:30:00 +0100Modules whose direct summands are FI-extending
http://bims.iranjournals.ir/article_1091_0.html
‎A module $M$ is called FI-extending if every fully invariant submodule of $M$ is essential in a direct summand of $M$‎. ‎It is not known whether a direct summand of an FI-extending module is also FI-extending‎. ‎In this study‎, ‎it is given some answers to the question that under what conditions a direct summand of an FI-extending module is an FI-extending module?Sun, 12 Mar 2017 20:30:00 +0100On the facet ideal of an expanded simplicial complex
http://bims.iranjournals.ir/article_1092_0.html
For a simplicial complex $Delta$, the affect of the expansion functor on combinatorial properties of $Delta$ and algebraic properties of its Stanley-Reisner ring has been studied in some previous papers.
In this paper, we consider the facet ideal $I(Delta)$ and its Alexander dual which we denote by $J_{Delta}$ to see how the expansion functor alter the algebraic properties of these ideals. It is shown that for any expansion $Delta^{alpha}$ the ideals $J_{Delta}$ and $J_{Delta^{alpha}}$ have the same total Betti numbers and their Cohen-Macaulayness are equivalent, which implies that the regularities of the ideals $I(Delta)$ and $I(Delta^{alpha})$ are equal. Moreover, the projective dimensions of $I(Delta)$ and $I(Delta^{alpha})$ are compared.
In the sequel for a graph $G$, some properties that are equivalent in $G$ and its expansions are presented and for a Cohen-Macaulay (resp. sequentially Cohen-Macaulay and shellable) graph $G$, we give some conditions for adding or removing a vertex from $G$, so that the remaining graph is still Cohen-Macaulay (resp. sequentially Cohen-Macaulay and shellable).Sun, 12 Mar 2017 20:30:00 +0100On the Stanley depth of powers of some classes of monomial ideals
http://bims.iranjournals.ir/article_1093_0.html
‎Given arbitrary monomial ideals $I$ and $J$ in polynomial rings $A$ and $B$ over a field $K$‎, ‎we investigate the Stanley depth of powers of the sum $I+J$‎, ‎and their quotient rings‎, ‎in $Aotimes_K B$ in terms of those of $I$ and $J$‎. ‎Our results can be used to study the asymptotic behavior of the Stanley depth of powers of a monomial ideal‎. ‎We tackle the case when $J$ is a monomial complete intersection‎.Sun, 12 Mar 2017 20:30:00 +0100Commuting mappings on the Hochschild extension of an algebra
http://bims.iranjournals.ir/article_1094_0.html
In this paper we will describe the general form of commuting mappings of Hochschild extension algebras and characterize the properness of commuting mappings on a special class of Hochschild extension algebras with the so-called $p.$Sun, 12 Mar 2017 20:30:00 +0100The $w$-FF property in trivial extensions
http://bims.iranjournals.ir/article_1095_0.html
‎Let $D$ be an integral domain with quotient field $K$‎, ‎$E$ be a $K$-vector space‎, ‎$R = D propto E$ be the trivial extension of $D$ by $E$‎, ‎and $w$ be the so-called $w$-operation‎. ‎In this paper‎, ‎we show that‎ ‎$R$ is a $w$-FF ring if and only if $D$ is a $w$-FF domain; and‎ ‎in this case‎, ‎each $w$-flat $w$-ideal of $R$ is $w$-invertible.Sun, 12 Mar 2017 20:30:00 +0100Duality for the class of a multiobjective problem with support functions under ...
http://bims.iranjournals.ir/article_1096_0.html
‎In this article‎, ‎we formulate two dual models Wolfe and Mond-Weir related to symmetric nondifferentiable multiobjective programming problems‎. ‎Furthermore‎, ‎weak‎, ‎strong and converse duality results are established under $K$-$G_f$-invexity assumptions‎. ‎Nontrivial examples have also been depicted to illustrate the theorems obtained in the paper‎. ‎Results established in this paper unify and extend some previously known results appeared in the literatureSun, 12 Mar 2017 20:30:00 +0100Quasi-Frobenius amalgamated algebras
http://bims.iranjournals.ir/article_1097_0.html
‎Let $f:Arightarrow B$ be a homomorphism of commutative rings and let $J$ be an ideal of $B$‎. ‎The amalgamation of $A$ with $B$ along $J$ with respect to $f$ is the subring of $Atimes B$ given by $Abowtie^fJ={(a,f(a)+j)mid ain A‎, ‎jin J}$‎. ‎In this paper‎, ‎we give some characterizations for the amalgamation construction‎ ‎to be a quasi-Frobenius ring.Sun, 12 Mar 2017 20:30:00 +0100Localization at prime ideals in bounded rings
http://bims.iranjournals.ir/article_1098_0.html
In this paper we investigate the sufficiency criteria which guarantee the classical localization of a bounded ring at its prime ideals.Sun, 12 Mar 2017 20:30:00 +0100On regular sequences in the form module with applications to local B'ezout inequalities
http://bims.iranjournals.ir/article_1099_0.html
‎Let $mathfrak{q}$ denote an ideal in a Noetherian local ring $(A,mathfrak{m})$‎. ‎Let $underline a=a_1,ldots,a_d subset mathfrak{q}$ denote a system of parameters in a finitely generated $A$-module $M$‎. ‎This note investigate an improvement of the inequality $c_1cdot ldots cdot c_d cdot e_0(mathfrak{q};M) leq ell_A(M/underline a,M)$‎, ‎where $c_i$ denote the initial degrees of $a_i$ in the form ring $G_A(mathfrak{q})$‎. ‎To this end‎, ‎there is an investigation of regular sequences in the form module $G_M(mathfrak{q})$ by homology of a factor complex of the Koszul complex‎. ‎In a particular case‎, ‎there is a discussion of classical local B'ezout inequality in the affine $d$-space $mathbb{A}^d_k$.Sun, 12 Mar 2017 20:30:00 +0100On the unstable Hurewicz homomorphism and Toda brackets
http://bims.iranjournals.ir/article_1100_0.html
‎The aim of this note is to examine the Curtis conjecture in the light of existing structural results about the $2$-primary part of the stable homotopy ring‎. ‎Motivated by Joel Cohen's result on generating stable stems using higher Toda brackets‎, ‎we obtain sufficient conditions for vanishing of the unstable Hurewicz homomorphism ${_2pi_*^s}simeq {_2pi_*}QS^0to H_*(QS^0;Z/2)$‎. ‎We also record some partial results on the relation between $EHP$-sequence and the behaviour of Hurewicz homomorphism.Sun, 12 Mar 2017 20:30:00 +0100Existence and multiplicity results for Steklov problems with $p(.)$-Growth conditions
http://bims.iranjournals.ir/article_1101_0.html
‎Using variational methods‎, ‎we prove in‎ ‎different situations the existence and multiplicity of solutions‎ ‎for the following Steklovmbox{ problem}‎ $$‎begin{gathered}‎
‎-mbox{div}(a(x,‎ ‎nabla u))+|u|^{p(x)-2}u=0‎, ‎quad‎
‎text{in }Omega‎, ‎\‎
‎a(x‎, ‎nabla u).nu=g(x,u)‎, ‎quad text{on } partialOmega‎,
‎end{gathered}‎
$$
‎where $Omegasubsetmathbb{R}^N(N geq 2)$ is a bounded domain with ‎smooth boundary $partialOmega$ and $nu$ is the unit outward normal‎ ‎vector on $partialOmega$‎. ‎$ p‎: ‎overline{Omega} mapsto‎ ‎mathbb{R}$‎, ‎$a‎: ‎overline{Omega}times mathbb{R}^{N} mapsto‎ ‎mathbb{R}^{N}$ and $g‎: ‎partialOmegatimesmathbb{R} mapsto mathbb{R}$ are fulfilling appropriate conditions.Sun, 12 Mar 2017 20:30:00 +0100$L^p$ boundedness of the Bergman projection on some generalized Hartogs triangles
http://bims.iranjournals.ir/article_1102_0.html
‎In this paper we investigate a two classes of domains in $mathbb{C}^n$ generalizing the Hartogs triangle‎. ‎We prove optimal estimates for the mapping properties of the Bergman projection on these domains.Sun, 12 Mar 2017 20:30:00 +0100On the fixed number of graphs
http://bims.iranjournals.ir/article_1103_0.html
‎A set of vertices $S$ of a graph $G$ is called a fixing set of $G$‎, ‎if only the trivial automorphism of $G$ fixes every vertex in $S$‎. ‎The fixing number of a graph is the smallest cardinality of a fixing‎ ‎set‎. ‎The fixed number of a graph $G$ is the minimum $k$‎, ‎such that ‎every $k$-set of vertices of $G$ is a fixing set of $G$‎. ‎A graph $G$‎ ‎is called a $k$-fixed graph‎, ‎if its fixing number and fixed number‎ ‎are both $k$‎. ‎In this paper‎, ‎we study the fixed number of a graph‎ ‎and give a construction of a graph of higher fixed number from a‎ ‎graph of lower fixed number‎. ‎We find the bound on $k$ in terms of‎ ‎the diameter $d$ of a distance-transitive $k$-fixed graph‎.Sun, 12 Mar 2017 20:30:00 +0100Filter theory in MTL-algebras based on Uni-soft property
http://bims.iranjournals.ir/article_1104_0.html
‎The notion of (Boolean) uni-soft filters‎ ‎in MTL-algebras is introduced‎, ‎and several properties of them are‎ ‎investigated‎. ‎Characterizations of (Boolean) uni-soft filters are discussed‎, ‎and some (necessary and sufficient) conditions‎ ‎for a uni-soft filter to be Boolean are provided‎.
‎The condensational property for a Boolean uni-soft filter is established.Sun, 12 Mar 2017 20:30:00 +0100Gromov hyperbolicity in the Cartesian sum of graphs
http://bims.iranjournals.ir/article_1105_0.html
‎In this paper we characterize the hyperbolic product graphs for the Cartesian sum $G_1oplus G_2$‎: ‎$G_1oplus G_2$ is always hyperbolic‎, ‎unless either $G_1$ or $G_2$ is the trivial graph (the graph with a single vertex); if $G_1$ or $G_2$ is the trivial graph‎, ‎then $G_1oplus G_2$ is hyperbolic if and only if $G_2$ or $G_1$ is hyperbolic‎, ‎respectively‎. ‎Besides‎, ‎we characterize the Cartesian sums with hyperbolicity constant $delta(G_1oplus G_2) = t$ for every value of $t$‎. ‎Furthermore‎, ‎we obtain the sharp inequalities $1le delta(G_1oplus G_2)le 3/2$ for every non-trivial graphs $G_1,G_2$‎. ‎Also‎, ‎we obtain simple formulas for the hyperbolicity constant of the Cartesian sum of many graphs‎. ‎Finally‎, ‎we prove the inequalities $3/2le delta(overline{G_1oplus G_2})le 2$ for the complement graph of $G_1oplus G_2$ for every $G_1,G_2$ with $min{diam V(G_1)‎, ‎diam V(G_2)}ge 3$.Sun, 12 Mar 2017 20:30:00 +0100Some applications of differential subordinations for generalized Bessel functions
http://bims.iranjournals.ir/article_1106_0.html
Some novel applications of differential subordinations for meromorphically multivalent functions with an operator involving the generalized Bessel functions are given.Sun, 12 Mar 2017 20:30:00 +0100Determination of a jump by Fourier and Fourier-Chebyshev series
http://bims.iranjournals.ir/article_1107_0.html
‎By observing the equivalence of assertions on determining the jump of a‎ ‎function by its differentiated or integrated Fourier series‎, ‎we generalize a‎ ‎previous result of Kvernadze‎, ‎Hagstrom and Shapiro to the whole class of‎ ‎functions of harmonic bounded variation‎. ‎This is achieved without the finiteness assumption on‎ ‎the number of discontinuities‎. ‎Two results on determination of jump‎ ‎discontinuities by means of the tails of integrated Fourier-Chebyshev series are also derived.Sun, 12 Mar 2017 20:30:00 +0100Multiple solutions for fractional boundary value problems
http://bims.iranjournals.ir/article_1108_0.html
Variational methods and critical point theorems are usedto discuss existence and multiplicity of solutions for fractionalboundary value problem where Riemann-Liouville fractionalderivatives and Caputo fractional derivatives are used. Someconditions to determinate nonnegative solutions are presented. Anexample is given to illustrate our results.Wed, 15 Mar 2017 20:30:00 +0100Improved logarithmic-geometric mean inequality and its application
http://bims.iranjournals.ir/article_1110_0.html
In this short note, we present a refinement of the logarithmic-geometric mean inequality. As an application of our result, we obtain an operator inequality associated with geometric and logarithmic means.Mon, 27 Mar 2017 19:30:00 +0100Theorems of Burnside and Wedderburn revisited
http://bims.iranjournals.ir/article_1111_0.html
We approach celebrated theorems of Burnside and Wedderburn via simultaneous triangularization. First, for a general field $F$, we prove that $M_n(F)$ is the only irrreducible subalgebra of triangularizable matrices in $M_n(F)$ provided such a subalgebra exists. This provides a slight generalization of a well-known theorem of Burnside. Next, for a given $n > 1$, we characterize all fields $F$ such that Burnside's Theorem holds in $M_n(F)$, i.e., $M_n(F)$ is the only irreducible subalgebra of itself. In fact, for a subfield $F$ of the center of a division ring $D$, our simple proof of the aforementioned extension of Burnside's Theorem can be adjusted to establish a Burnside type theorem for irreducible $F$-algebras of triangularizable matrices in $M_n(D)$ with inner eigenvalues in $F$, namely such subalgebras of $M_n(D)$ are similar to $M_n(F)$. We use Burnside's theorem to present a simple proof of a theorem due to Wedderburn. Then, we use our Burnside type theorem to prove an extension of Wedderburn's Theorem as follows: A subalgebra of a semi-simple left Artinian $F$-algebra is nilpotent iff the algebra, as a vector space over the field $F$, is spanned by its nilpotent members and that the minimal polynomials of all of its members split into linear factors over $F$. We conclude with an application of Wedderburn's Theorem.Mon, 27 Mar 2017 19:30:00 +0100Some refinement for the arithmetic-geometric mean and Cauchy-Schwartz matrix norm interpolating ...
http://bims.iranjournals.ir/article_1112_0.html
Recently, some inequalities were established that interpolates between the arithmetic-geometric mean inequality and the Cauchy-Schwarz inequality for matrices. In this paper, by a dierent approach we give several renements for these inequalities.Tue, 04 Apr 2017 19:30:00 +0100On rational groups with Sylow 2-subgroups of nilpotency class at most 2
http://bims.iranjournals.ir/article_1113_0.html
A finite group $G$ is called rational if all its irreducible complex characters are rational valued. In this paper we discuss about rational groups with Sylow 2-subgroups of nilpotency class at most 2 by imposing the solvability and nonsolvability assumption on $G$ and also via nilpotency and nonnilpotency assumption of $G$.Thu, 06 Apr 2017 19:30:00 +0100G-symplectic integration of many body problems
http://bims.iranjournals.ir/article_1114_0.html
The purpose of this paper is to derive a symmetric parasitic free G-symplectic general linear method of order four and apply it to problems in celestial mechanics. The numerical method is constructed by satisfying the G-symplectic conditions for general linear methods, together with relevant order conditions while making sure that there is zero parasitism.The internal stages are designed to be diagonally implicit to make the method more efficient. Being multivalue in nature, a starting method is required for the implementation of general linear method and this is also calculated using rooted trees. The general linear method is applied to many body problems and acceptable error in energy and global error areobserved.Tue, 11 Apr 2017 19:30:00 +0100Historic set carries full hausdorff dimension
http://bims.iranjournals.ir/article_1115_0.html
We prove that the historic set for ratioof birkhoff average is either empty or full of Hausdorff dimension in a class of one dimensionalnon-uniformly hyperbolic dynamic systems.Wed, 12 Apr 2017 19:30:00 +0100On subgroups of topologized fundamental groups and generalized coverings
http://bims.iranjournals.ir/article_1116_0.html
‎In this paper‎, ‎we are interested in study subgroups of topologized fundamental groups and their influences on generalized covering maps‎.
‎More precisely‎, ‎we find some relationships between generalized covering subgroups and the other famous subgroups of the fundamental group equipped with the compact-open topology and the whisker topology‎. ‎Moreover‎, ‎we present some conditions under which generalized coverings‎, ‎semicoverings and coverings are equal.Mon, 17 Apr 2017 19:30:00 +0100Weighted composition operators on differentiable Lipschitz algebras
http://bims.iranjournals.ir/article_1117_0.html
‎Let $Lip^n(X‎, ‎al)$ be the algebra of complex-valued functions on ‎a perfect compact plane set $X$ whose derivatives up to order $n$‎ ‎exist and satisfy the Lipschitz condition of order $0<alleq 1$‎. ‎We establish a necessary and sufficient condition for a weighted‎ ‎composition operator on $Lip^n(X‎, ‎al)$ to be compact‎. ‎To obtain‎ ‎the necessary condition in the case $0<al < 1$‎, ‎we provide a‎ ‎relation between these algebras and Zygmund type spaces‎ ‎$mathcal{Z}_n^al$‎. ‎We then conclude some interesting results about weighted‎ ‎composition operators on $mathcal{Z}_n^al$ and determine the‎ ‎spectra of these operators when they are compact or Riesz.Mon, 17 Apr 2017 19:30:00 +0100Strong linear preserver of dense-matrices
http://bims.iranjournals.ir/article_1118_0.html
‎Let $textbf{M}_{m,n}$ be the set of all $mtimes n$ real matrices‎. ‎A matrix $Ain textbf{M}_{m,n}$ is said to be a dense-matrix if there‎ ‎are no zeros between two non-zero entries for every line (row or column) of‎ ‎this matrix‎. ‎In this paper we find the structure of linear maps $T:textbf{M}_{m,n} rightarrow textbf{M}_{m,n}$ that strongly preserve dense-matrices‎, ‎i.e‎. ‎$T(A)$ is a dense-matrix if and only if‎ ‎$A$ is a dense-matrix‎.Tue, 18 Apr 2017 19:30:00 +0100Hölder continuity of a parametric variational inequality
http://bims.iranjournals.ir/article_1120_0.html
In this paper, we study the Hölder continuity of solution mapping to a parametric variational inequality. At first, recalling a real-valued gap function of the problem, we discuss the Lipschitz continuity of the gap function. Then under the strong monotonicity, we establish the Hölder continuity of the single-valued solution mapping for the problem. Finally, we apply these results to a traffic network equilibrium problem.Mon, 01 May 2017 19:30:00 +0100Self-similar solutions of the Riemann problem for two-dimensional systems of ...
http://bims.iranjournals.ir/article_1121_0.html
In this paper, a new approach is applied to study the self-similar solutions of 2×2 systems of nonlinear hyperbolic conservation laws. A notion of characteristic directions is introduced and then used to construct local and smooth solutions of the associated Riemann problemTue, 02 May 2017 19:30:00 +0100Some extensions of the Young and Heinz inequalities for matrices
http://bims.iranjournals.ir/article_1122_0.html
In this paper, we present some extensions of the Young and Heinz inequalitiesfor the Hilbert-Schmidt norm as well as any unitarily invariant norm. Furthermore,we give some inequalities dealing with matrices. More precisely, for two positive semidefinite matrices $A$ and $B$ we show that begin{align*}Big|A^{nu}XB^{1-nu}+A^{1-nu}&XB^{nu}Big|_{2}^{2}leqBig|AX+XBBig|_{2}^{2}-2rBig|AX-XBBig|_{2}^{2}&,,-r_{0}left(Big|A^{frac{1}{2}}XB^{frac{1}{2}}-AXBig|_{2}^{2}+Big|A^{frac{1}{2}}XB^{frac{1}{2}}-XBBig|_{2}^{2}right),end{align*}where $X$ is an arbitrary $ntimes n$ matrix, $0Thu, 04 May 2017 19:30:00 +0100Existence and uniqueness of weak solutions for a class of nonlinear divergence type diffusion ...
http://bims.iranjournals.ir/article_1123_0.html
In this paper, we study the Neumann boundary value problem of a class of nonlinear parabolic equations. By a priori estimates, difference and variation techniques, we establish the existence and uniqueness of weak solutions of this problem.Thu, 04 May 2017 19:30:00 +0100On a maximal parabolic subgroup of $O^{+}_{8}(2)$
http://bims.iranjournals.ir/article_1124_0.html
The simple orthogonal group $O^{+}_{8}(2)$ has a maximal parabolic subgroup of the form $bar{G}=N{:}G$ where $N=2^{6}$ and $Gcong A_{8}$. Using Atlas, we can see that $O^{+}_{8}(2)$ has three maximal subgroups of type $2^6{:}A_{8}$. These three maximal subgroups are conjugate in the full automorphism group of $O^{+}_{8}(2)$, namely $O^{+}_{8}(2){:}S_{3}$. Thus we have the modules $M_{1}=2^{6}$, $M_{2}=2^{6}$ and $M_{3}=2^{6}$ on which $A_{8}$ acts irreducibly (therefore these three modules are isomorphic as $O^{+}_{8}(2)-text{module}$). Without loss of generality, we can consider our maximal parabolic subgroup to be $bar{G}=M_{1}{:}A_{8}$. The Fischer matrices for each class representative of $G$ are computed which together with character tables of inertia factor groups of $G$ lead to the full character table of $bar{G}$. The complete fusion of $bar{G}$ into $O^{+}_{8}(2)$ has been determined using the technique of set intersections of characters.Sun, 07 May 2017 19:30:00 +0100Construction of implicit--explicit second derivative BDF methods
http://bims.iranjournals.ir/article_1125_0.html
In many applications, large systems of ordinary differential equations with both stiff and nonstiff parts have to be solvednumerically. Implicit-Explicit (IMEX) methods are useful for efficiently solving these problems. In this paper, we construct IMEX second derivative BDF (SDBDF) methods with considerable stability properties. To show the efficiency of the introduced technique, numerical comparisons are given by solving some problems.Tue, 09 May 2017 19:30:00 +0100Bounds for the dimension of the $c$-nilpotent multiplier of a pair of Lie algebras
http://bims.iranjournals.ir/article_1126_0.html
In 2009, Salemkar et al. extended the notion of the Schur multiplier of a Lie algebra to the c-nilpotent multiplier. In this paper, we study the c-nilpotent multiplier of a pair of Lie algebras and give some inequalities for the dimension of the $c$-nilpotent multiplier of a pair of Lie algebras.Wed, 10 May 2017 19:30:00 +0100Solving two-dimensional fractional integro-differential equations by Legendre wavelets
http://bims.iranjournals.ir/article_1127_0.html
‎‎‎In this paper‎, ‎we first introduce the two-dimensional Legendre wavelets(2D-LWs)‎, ‎then we develop them for solving a class of two-dimensional integro-differential equations(2D-IDEs) of fractional order‎. ‎We also investigate convergence of the method‎. ‎Finally‎, ‎we give some illustrative examples to demonstrate the validity and efficiency of the presented method.Wed, 10 May 2017 19:30:00 +0100Extensions of the Hestenes-Stiefel and Polak-Ribiere-Polyak conjugate gradient methods with ...
http://bims.iranjournals.ir/article_1128_0.html
Using search directions of a recent class of three--term conjugate gradient methods, modified versions of the Hestenes-Stiefel and Polak-Ribiere-Polyak methods are proposed which satisfy the sufficient descent condition. The methods are shown to be globally convergent when the line search fulfills the (strong) Wolfe conditions. Numerical experiments are done on a set of CUTEr unconstrained optimization test problems. They demonstrate efficiency of the proposed methods in the sense of the Dolan-More performance profile.Sun, 14 May 2017 19:30:00 +0100Minimal free resolution of monomial ideals by iterated mapping cone
http://bims.iranjournals.ir/article_1129_0.html
‎In this paper we study minimal free resolutions of some classes of‎ ‎monomial ideals‎. ‎we first give a ‎sufficient condition to check the minimality of the resolution‎ ‎obtained by the mapping cone‎. ‎Using it‎, ‎we obtain the Betti numbers of max-path ideals of‎ ‎rooted trees and ideals containing‎ ‎powers of variables‎. ‎In particular‎, ‎we discuss about resolutions of ideals of the form $J_{mathcal{H}}+(x_{i_1}^2,ldots‎, ‎x_{i_m}^2)$ where $J_{mathcal{H}}$ is the edge ideal of a hypergraph $mathcal{H}$.Thu, 18 May 2017 19:30:00 +0100Yamabe solitons on three-dimensional $N(k)$-paracontact metric manifolds
http://bims.iranjournals.ir/article_1130_0.html
‎We prove that if a three-dimensional $N(k)$-paracontact metric manifold admits a Yamabe soliton $(g,xi)$‎, ‎then the scalar curvature is constant and the manifold is a paraSasakian manifold‎. ‎Moreover‎, ‎we show that if a three-dimensional $N(k)$-paracontact metric manifold admits a Yamabe soliton $(g,V)$‎, ‎then either the manifold is a space of constant curvature‎, ‎or the flow vector field $V$ is Killing.Mon, 12 Jun 2017 19:30:00 +0100Certain generating relations of generalized Bessel matrix polynomials from the view point of ...
http://bims.iranjournals.ir/article_1133_0.html
The main objective of the present paper is to derive the integral representation, matrix recurrence relations and matrix differential recurrence relations for the generalized Bessel matrix polynomials. Furthermore, we obtain a class of generating matrix functions for the generalized Bessel matrix polynomials by using the representation of a Lie group theory with the aid of Weisner's method. Some particular cases of interest as well as the applications of our results are also presented out.Thu, 27 Jul 2017 19:30:00 +0100Differentiability and subdifferentiability on semilinear spaces
http://bims.iranjournals.ir/article_1134_0.html
In this paper, a new differentiability theory for mappings between semilinear spaces is introduced so that it improves Galanis's definition. We also introduce the notion of subdifferentiability and proceed with the study of some related properties of these concepts.Under appropriate conditions, it is shown that the subdifferential of a differentiable function on a topological semilinear space is singleton.Thu, 27 Jul 2017 19:30:00 +0100Notes on generalized derivations and partial generalized automorphisms in prime rings
http://bims.iranjournals.ir/article_1135_0.html
‎In this paper‎, ‎we obtain several results on generalized derivations and partial generalized automorphisms in prime‎ ‎rings‎. ‎Also‎, ‎some examples are given to show that the restrictions imposed on the hypothesis of‎ ‎the various results can not be omitted.Thu, 27 Jul 2017 19:30:00 +0100More inequalities for sector matrices
http://bims.iranjournals.ir/article_1136_0.html
Several inequalities are presented for sector matrices. Firstly, an analogue of the GM-HM inequality is established. As applications of this inequality, similar inequalities are presented for singular values and norms. Finally, some unitarily invariant norm inequalities are obtained for sector matrices.Thu, 27 Jul 2017 19:30:00 +0100On a Picone's identity for the $mathcal{A}_{p(x)}$-Laplacian and its applications
http://bims.iranjournals.ir/article_1137_0.html
‎We present a Picone's identity for the‎ ‎$mathcal{A}_{p(x)}$-Laplacian‎, ‎which is an extension of the classic‎ ‎identity for the ordinary Laplace‎. ‎Also‎, ‎some applications of our‎ ‎results in Sobolev spaces with variable exponent are suggested.Fri, 28 Jul 2017 19:30:00 +0100Laplacians and Legendre surfaces in pseudo-Hermitian geometry
http://bims.iranjournals.ir/article_1138_0.html
‎In this paper‎, ‎we prove that for a Legendre surface $N$ of 5-dimensional Sasakian space forms $M^5$‎,
‎if $N$ satisfies $hattriangle H=lambda H$ and‎
‎$mathrm{tr}hatnabla>hat T(H)=0$ for a constant $lambda$‎,
‎then $|H|$ is a constant‎
‎if and only if $H$ is $hat D$-parallel‎, ‎$N$ is a Chen surface‎, ‎and $tr S^2_{H}=lambda parallel H parallel$‎.
‎From this‎, ‎for a Legendre surface $N$ of $M^5$ such that $|H|$ is a constant‎, ‎if $N$ satisfies $hattriangle H=lambda H$ and‎ ‎$mathrm{tr}hatnabla>hat T(H)=0$ for a constant $lambda$‎, ‎then $N$ is $hat D$-parallel Legendre Chen surfaces‎.
‎Moreover‎, ‎we show that it is minimal‎, ‎or locally product of‎ ‎a geodesic and a pseudo-Hermitian circle or two pseudo-Hermitian circles.Wed, 02 Aug 2017 19:30:00 +0100Groups of prime power orders covered by a certain number of proper subgroups
http://bims.iranjournals.ir/article_1139_0.html
‎Let $G$ be a group‎. ‎A set of proper subgroups of $G$ is called a cover or covering for $G$ if its set-theoretic union is equal to $G$‎. ‎A cover for $G$ is called irredundant if every proper subset of the cover is not again a cover for $G$‎. ‎Yakov Berkovich proposed the following problem:
‎Does there exist a $p$-group $G$ admitting an irredundant covering by $n$ subgroups‎, ‎where $p+1<n<2p$? If `yes'‎, ‎classify such groups. ‎We prove that for any prime $pgeq 3$‎, ‎every finite $p$-group whose minimum number of generators is at least $3$ has an irredundant cover of size $frac{3(p+1)}{2}$‎. ‎It follows that the classification of all finite $p$-groups having an irredundant covering of size $n$ where $p+1<n<2p$ is not possible‎. Wed, 02 Aug 2017 19:30:00 +0100Characterizations of graded Prüfer $\star$-multiplication domains, II
http://bims.iranjournals.ir/article_1140_0.html
‎Let $R=bigoplus_{alphainGamma}R_{alpha}$ be a graded integral‎ ‎domain and $star$ be a semistar operation on $R$‎. ‎For $ain R$‎, ‎denote by $C(a)$ the ideal of $R$ generated by homogeneous‎ ‎components of $a$ and for $f=f_0+f_1X+cdots+f_nX^nin R[X]$‎, ‎let‎ ‎$A_f:=sum_{i=0}^nC(f_i)$‎. ‎Let $N(star):={fin R[X]mid‎ ‎fneq0text{ and }A_f^{star}=R^{star}}$‎. ‎In this paper we study‎ ‎relationships between ideal theoretic properties of‎ ‎$NA(R,star):=R[X]_{N(star)}$ and the homogeneous ideal theoretic‎ ‎properties of $R$‎. ‎For example we show that $R$ is a graded‎ ‎Prüfer-$star$-multiplication domain if and only if‎ ‎$NA(D,star)$ is a Prüfer domain if and only if $NA(R,star)$‎ ‎is a B'{e}zout domain‎. ‎We also determine when $NA(R,v)$ is a PID.Wed, 02 Aug 2017 19:30:00 +0100Linear preservers of ${\rm D}$-majorization
http://bims.iranjournals.ir/article_1141_0.html
‎An even signed permutation matrix is a matrix that contains precisely one 1 or‎ -‎1 in each row and each column and all other entries equal to zero with the property that the number of‎ -‎1s is even‎. ‎In this paper‎, ‎using even signed permutation matrices‎, ‎the concept of ${rm D}$-majorization is introduced‎. ‎Then the linear preservers of ${rm D}$-majorization on $ mathbb{R}^{n}$ and ${M_{n,m}}$ are characterized‎.Thu, 03 Aug 2017 19:30:00 +0100Existence of three solutions for a discrete anisotropic boundary value problem
http://bims.iranjournals.ir/article_1142_0.html
‎The existence of three solutions for a anisotropic discrete non-linear problem‎ ‎involving $p(k)$-Laplacian operator with Dirichlet boundary value‎ ‎conditions depending on two parameters‎, ‎is investigated‎. ‎Variational approach is applied based on a critical point theorem‎ ‎due to Bonanno‎, ‎Candito and D'Agui.Thu, 17 Aug 2017 19:30:00 +0100Connes-amenability of $WAP(fB^*)^*$
http://bims.iranjournals.ir/article_1143_0.html
‎For a Banach algebra $frak b$‎, ‎the set of weakly almost periodic functions on $frak b$ is denoted by $WAP(frak b^*)$‎. ‎It is known that amenability of $frak b$ yields Connes-amenability of $WAP(frak b^*)^*$‎. ‎The converse is not generally true though‎. ‎We prove that under certain assumptions‎, ‎$frak b$ is amenable if and only if $WAP(frak b^*)^*$ is Connes-amenable‎. ‎As a result‎, ‎we show that for a reflexive Banach space $E$ with the approximation property‎, ‎$K(E)$ is amenable if and only if $WAP(K(E)^*)^*$ is Connes-amenable‎.Wed, 23 Aug 2017 19:30:00 +0100Riemannian geometry of two families of tangent Lie groups
http://bims.iranjournals.ir/article_1144_0.html
Using vertical and complete lifts, any left invariant Riemannian metric on a Lie group induces a left invariant Riemannian metric on the tangent Lie group. In the present article we study the Riemannian geometry of tangent bundle of two families of real Lie groups. The first one is the family of special Lie groups considered by J. Milnor and the second one is the class of Lie groups with one-dimensional commutator groups. The Levi-Civita connection, sectional and Ricci curvatures have been investigated.Fri, 08 Sep 2017 19:30:00 +0100A Reflected inertial Krasnoselskii type Algorithm for Lipschitz pseudo-contractive mappings
http://bims.iranjournals.ir/article_1145_0.html
It is well-known that Mann's algorithm fails to converge for Lipschitz pseudo-contractive mappings and strong convergence of Ishikawa's algorithm for Lipschitz pseudo-contractive mappings T have not been achieved without compactness assumption on T or on the underlying closed convex set C. In this note, we develop a convergence result of a Reflected inertial Krasnoselskii type Algorithm for nding xed-points of Lipschitz pseudo-contractive mappings in Hilbert spaces with an application to a split feasibility/fixed-point problem.Fri, 08 Sep 2017 19:30:00 +0100On the Noetherian dimension of Artinian modules with homogeneous uniserial dimension
http://bims.iranjournals.ir/article_1146_0.html
‎In this article‎, ‎we first‎ ‎show that non-Noetherian Artinian uniserial modules over‎ ‎commutative rings‎, ‎duo rings‎, ‎finite $R$-algebras and right‎ ‎Noetherian rings are $1$-atomic exactly like $Bbb Z_{p^{infty}}$‎. ‎Consequently‎, ‎we show that if $R$ is a right duo (or‎, ‎a right‎ ‎Noetherian) ring‎, ‎then the Noetherian dimension of an Artinian‎ ‎module with homogeneous uniserial dimension is less than or equal‎ ‎to $1$‎. ‎In particular‎, ‎if $A$ is a quotient finite dimensional‎ ‎$R$-module with homogeneous uniserial dimension‎, ‎where $R$ is a‎ ‎locally Noetherian (or‎, ‎a Noetherian duo) ring‎, ‎then $ndim‎, ‎Aleq‎ ‎1$‎. ‎We also show that the Krull dimension of Noetherian modules is‎ ‎bounded by the uniserial dimension of these modules‎. ‎Moreover‎, ‎we introduce the concept of qu-uniserial modules and by using this‎ ‎concept‎, ‎we observe that if $A$ is an Artinian $R$-module‎, ‎such that‎ ‎any of its submodules is qu-uniserial‎, ‎where $R$ is a right duo (or‎, ‎a right Noetherian) ring‎, ‎then $ndim‎, ‎Aleq 1$.Fri, 08 Sep 2017 19:30:00 +0100Derivations of commutative residuated lattices
http://bims.iranjournals.ir/article_1147_0.html
‎In this short note we consider some properties of derivations of commutative residuated lattices and show that‎, ‎for any residuated lattice $X$‎,
(i) if $d$ is a monotone derivation and $d1in B(X)$ then it is characterized by $dx = x'' wedge d1$;‎ (ii) if $X$ is a linearly ordered R$ell$-monoid and $d$ is an additive derivation then the derivation $d$ has only two cases $d1=1$ or $d=0$;‎ (iii) the notion of a monotone derivation is identical with that of an additive derivation in every MV-algebra‎.Fri, 15 Sep 2017 19:30:00 +0100Distinguishing number and distinguishing index of natural and fractional powers of graphs
http://bims.iranjournals.ir/article_1148_0.html
‎The distinguishing number (index) $D(G)$ ($D'(G)$) of a graph $G$ is the least integer $d$‎ ‎such that $G$ has an vertex labeling (edge labeling) with $d$ labels that is preserved only by a trivial‎ ‎automorphism‎. ‎For any $n in mathbb{N}$‎, ‎the $n$-subdivision of $G$ is a simple graph $G^{frac{1}{n}}$ which is constructed by replacing each edge of $G$ with a path of length $n$‎. ‎The $m^{th}$ power of $G$‎, ‎is a graph with same set of vertices of $G$ and an edge between two vertices if and only if there is a path of length at most $m$ between them in $G$.‎ The fractional power of $G$‎, ‎is $m^{th}$ power of the $n$-subdivision of $G$‎, ‎i.e.‎, ‎$(G^{frac{1}{n}})^m$ or $n$-subdivision of $m$-th power of $G$‎, ‎i.e.‎, ‎$(G^m)^{frac{1}{n}}$‎. ‎In this paper we study the distinguishing number and the distinguishing index of the natural and the fractional powers of $G$‎. ‎We show that the natural powers more than one of a graph distinguished by at most three edge labels‎. ‎We also show that for a connected graph $G$ of order $n geqslant 3$ with maximum degree $Delta (G)$‎, ‎and for $kgeqslant 2$‎, ‎$D(G^{frac{1}{k}})leqslant lceil sqrt[k]{Delta (G)} rceil$‎. ‎Finally we prove that for $mgeqslant 2$‎, ‎the fractional power of $G$‎, ‎i.e.‎, ‎$(G^{frac{1}{k}})^m$ and $(G^m)^{frac{1}{k}}$ distinguished‎ ‎ by at most three edge labels‎.Mon, 18 Sep 2017 19:30:00 +0100Nontrivial weak solution for a Schrödinger-Kirchhoff-type system driven by a ...
http://bims.iranjournals.ir/article_1149_0.html
‎In this paper‎, ‎we investigate the existence of nontrivial weak solution for a Schrödinger-Kirchhoff-type system driven by a‎ ‎$(p_1,p_2)$-Laplacian operator under appropriate hypotheses‎. ‎The proofs are based on‎ ‎the variational methods.Mon, 25 Sep 2017 20:30:00 +0100Almost automorphic solutions of non-autonomous differential equations
http://bims.iranjournals.ir/article_1150_0.html
In this paper we study the existence and uniqueness of almost automorphic solutions for non-autonomous linear and nonlinear differential equations in a Banach space, when the linear equation admits an exponential dichotomy.Tue, 26 Sep 2017 20:30:00 +0100Biclique Cover and Local Clique Cover of Graphs
http://bims.iranjournals.ir/article_1172_0.html
The biclique (resp. clique) cover number bc(G) (resp. cc(G))of a graph G is the smallest number of bicliques -complete bipartitesubgraphs- (resp. cliques -complete subgraphs-) of G such that everyedge of G belongs to at least one of these bicliques (resp. cliques). Ak-biclique (resp. k-clique )covering of a graph G, is an edge covering ofG by its bicliques (resp. cliques) such that each vertex is contained in atmost k bicliques (resp. cliques). The smallest k for which G admits a k-biclique (resp. clique) covering is called local biclique (resp. clique) covernumber of G and is denoted by lbc(G) (resp. lcc(G)). In this paper, weshow that bc(G) can be bounded in terms of lcc(G) and the number ofedges of the graph G. In particular, we show that if G is a graph withm edges then bc(G) ≤124lcc(G)lnm. As a result, we show that if G is agraph with m edges and G is a line graph then bc(G) ≤ 8lnm. Also,we exhibit some graphs such that the local clique cover number of theircomplements can be bounded in terms of their biclique cover number.Mon, 09 Oct 2017 20:30:00 +0100On some properties of Shelah cardinals
http://bims.iranjournals.ir/article_1173_0.html
‎We present several results concerning Shelah cardinals including the fact that small and fast function forcings preserve Shelah and $(^{kappa}kappacap V)$-Shelah cardinals respectively‎. ‎Furthermore we prove that the Laver Diamond Principle holds for Shelah cardinals and use this fact to show that Shelah cardinals can be made indestructible under $leq kappa$-directed closed forcings of size $<wt(kappa)$.Thu, 12 Oct 2017 20:30:00 +0100Characterization of $2\times 2$ full diversity space-time codes and inequivalent full rank spaces
http://bims.iranjournals.ir/article_1174_0.html
‎In wireless communication systems‎, ‎space-time codes are applied to encode data when multiple antennas are used in the receiver and transmitter‎. ‎The concept of diversity is very crucial in designing space-time codes‎. ‎In this paper‎, ‎using the equivalent definition of full diversity space-time codes‎, ‎we first characterize all real and complex $2times 2$ rate one linear dispersion space-time block codes that are full diversity‎. ‎This characterization is used to construct full diversity codes which are not derived from Alamouti scheme‎. ‎Then‎, ‎we apply our results to characterize all real subspaces of $M_{2}(mathbb{C})$ and $M_{2}(mathbb{R})$ whose nonzero elements are invertible‎. ‎Finally‎, ‎for any natural number $n>1$‎, ‎we construct infinitely many inequivalent subspaces of $M_{n}(mathbb{C})$ whose nonzero elements are invertible.Thu, 12 Oct 2017 20:30:00 +0100Solvability for a nonlinear matrix equation
http://bims.iranjournals.ir/article_1175_0.html
‎In this paper the matrix equation $X+sum_{i=1}^{m}A_{i}^*X^{-q_{i}}A_{i}=I$ with‎ ‎$0<q_{i}leq 1$ is investigated‎. ‎Based on the integral representation of matrix functions and‎ ‎the properties of Kronecker product‎, ‎we discuss the uniqueness of the Hermitian‎ ‎positive definite (HPD) solution of the above equation‎. ‎Some properties of the HPD solution are obtained.Sun, 15 Oct 2017 20:30:00 +0100Coradiant-valued maps and approximate solutions in variable ordering structures
http://bims.iranjournals.ir/article_1176_0.html
‎In this paper‎, ‎in order to introduce concepts of approximate efficiency in variable ordering structures‎, ‎some coradiant valued maps are used‎. ‎The concepts of approximate nondominated and minimal elements are defined and some of their properties are studied‎. ‎Corresponding to these concepts‎, ‎necessary and sufficient conditions are provided‎. ‎To obtain such conditions‎, ‎some scalarization methods are investigated‎. ‎This paper also investigates possible relationships among Pascoletti-Serafini radial scalarization and the approximate efficiency‎, ‎the approximate nondominance and minimality using some coradiant valued maps.Sun, 15 Oct 2017 20:30:00 +0100Groups with exactly ten centralizers
http://bims.iranjournals.ir/article_1177_0.html
‎In this article‎, ‎we determine all groups with exactly ten element centralizers‎. ‎Also we obtain the maximum size of the pairwise non-commuting elements of such groups‎.Sun, 15 Oct 2017 20:30:00 +0100Finite symmetric graphs with 2-arc-transitive quotients: General Affine case
http://bims.iranjournals.ir/article_1178_0.html
‎Let $G$ be a finite group and $Gamma$ a $G$-symmetric graph‎. ‎Suppose that $G$ is imprimitive on $V(Gamma)$ with $B$ a block of imprimitivity and $‎ ‎mathcal{B}‎ :‎= {B^g‎: ‎gin G}$ is a system of imprimitivity of $G$ on $V(Gamma)$‎. ‎Define $Gamma_{mathcal{B}}$ to be the graph with vertex set $mathcal{B}$ such that two blocks $B‎, ‎C in mathcal{B}$ are adjacent if and only if there exists at least one edge of $Gamma$ joining a vertex in $B$ and a vertex in $C$‎. ‎Set $v=|B|$ and $k‎ :‎= |Gamma(C)cap B|$ where $C$ is adjacent to $B$ in $Gamma_{mathcal{B}}$ and $Gamma(C)$ denotes the set of vertices of $Gamma$ adjacent to at least one vertex in $C$‎. ‎Assume that $k=v-pgeq1$‎, ‎where $p$ is an odd prime‎, ‎and $Gamma_{mathcal{B}}$ is $(G,2)$-arc-transitive‎. ‎In this paper we show that if the group induced on each block is an affine group then $v=6$.Sun, 15 Oct 2017 20:30:00 +0100