2018-05-23T13:28:30Z
http://bims.iranjournals.ir/?_action=export&rf=summon&issue=52
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Common fixed points of f-weak contractions in cone metric spaces
Wultipol
Sintunavarat
Poom
Kumam
Recently, Choudhury and Metiya [Fixed points of weak contractions in cone metric spaces, Nonlinear Analysis 72 (2010) 1589-1593] proved some fixed point theorems for weak contractions in cone metric spaces. Weak contractions are generalizations of the Banach's contraction mapping, which have been studied by several authors. In this paper, we introduce the notion of $f$-weak contractions and also establish a coincidence and common fixed point result for $f$-weak contractions in cone metric spaces. Our result is supported by an example which include and generalize the results of Choudhury and Metiya's work.
Cone metric spaces
Weak contraction
f-weak
contraction
coincidence point
common fixed point
2012
07
15
293
303
http://bims.iranjournals.ir/article_218_d595625aa45af7f415864e2b1458807a.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Rings with a setwise polynomial-like condition
Ali
Tavakoli
Alireza
Abdollahi
Howard E.
Bell
Let $R$ be an infinite ring. Here we prove that if $0_R$ belongs to ${x_1x_2cdots x_n ;|; x_1,x_2,dots,x_nin X}$ for every infinite subset $X$ of $R$, then $R$ satisfies the polynomial identity $x^n=0$. Also we prove that if $0_R$ belongs to ${x_1x_2cdots x_n-x_{n+1} ;|; x_1,x_2,dots,x_n,x_{n+1}in X}$ for every infinite subset $X$ of $R$, then $x^n=x$ for all $xin R$.
Primitive rings
Polynomial identities
Combinatorial conditions
2012
07
15
305
311
http://bims.iranjournals.ir/article_231_c96d633637c016b61c15d2693daeeffb.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
A new family in the stable homotopy groups of spheres
Xiugui
Liu
Kai
Ma
Let $p$ be a prime number greater than three. In this paper, we prove the existence of a new family of homotopy elements in the stable homotopy groups of spheres $pi_{ast}(S)$ which is represented by $h_nh_mtilde{beta}_{s+2}in {rm Ext}_A^{s+4, q[p^n+p^m+(s+2)p+(s+1)]+s}(mathbb{Z}_p,mathbb{Z}_p)$ up to nonzero scalar in the Adams spectral sequence, where $ngeq m+2>5$, $0leq sExt}_A^{s+2,q[(s+2)p+(s+1)]+s}(mathbb{Z}_p,mathbb{Z}_p)$ was defined by X. Wang and Q. Zheng.
stable homotopy groups of spheres
Adams spectral
sequence
May spectral sequence
2012
07
15
313
322
http://bims.iranjournals.ir/article_204_3e0a128f7a5b367bd3351fe6549af39e.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Branches in random recursive k-ary trees
Mehri
Javanian
Mohammad Q.
Vahidi Asl
In this paper, using generalized {polya} urn models we find the expected value of the size of a branch in recursive $k$-ary trees. We also find the expectation of the number of nodes of a given outdegree in a branch of such trees.
trees
random recursive trees
generalized
P'olya urn models
2012
07
15
323
331
http://bims.iranjournals.ir/article_200_0fb18b5d341305095aa3c67a34c101b0.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Horvitz-Thompson estimator of population mean under inverse sampling designs
Mohammad
Mohammadi
Mohammad
Salehi Marzijarani
Inverse sampling design is generally considered to be appropriate technique when the population is divided into two subpopulations, one of which contains only few units. In this paper, we derive the Horvitz-Thompson estimator for the population mean under inverse sampling designs, where subpopulation sizes are known. We then introduce an alternative unbiased estimator, corresponding to post-stratification approach. Both of these are not location-invariant, but this is ignorable for alternative estimator. Using a simulation study, we find that Horvitz-Thompson estimator is an efficient estimator when the mean of the off-interest subpopulation is close to zero while the alternative estimator appears to be an efficient estimator in general.
Finite Population
Inverse Sampling
Post-stratification
Random Sample Size
2012
07
15
333
347
http://bims.iranjournals.ir/article_255_8bc393a21f635d83fc2a4bdda66f1e39.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Comparison results on the preconditioned mixed-type splitting
iterative method for M-matrix linear systems
M.
Mohseni Moghadam
Fatemeh
Panjeh Ali Beik
Consider the linear system Ax=b where the coefficient matrix A is an M-matrix. In the present work, it is proved that the rate of convergence of the Gauss-Seidel method is faster than the mixed-type splitting and AOR (SOR) iterative methods for solving M-matrix linear systems. Furthermore, we improve the rate of convergence of the mixed-type splitting iterative method by applying a preconditioned matrix. Comparison theorems show that the rate of convergence of the preconditioned Gauss-Seidel method is faster than the preconditioned mixed-type splitting and AOR (SOR) iterative methods. Finally, some numerical examples are presented to illustrate the reality of our comparison theorems.
Linear systems
Mixed-type splitting iterative method
Preconditioned matrix
M-matrix
2012
07
15
349
367
http://bims.iranjournals.ir/article_211_dc5b9e9e1b2a179a471b622100c26a58.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
An iterative method for amenable semigroup and infinite family of non expansive mappings
in Hilbert spaces
Husain
Piri
Hamid
Vaezi
begin{abstract} In this paper, we introduce an iterative method for amenable semigroup of non expansive mappings and infinite family of non expansive mappings in the frame work of Hilbert spaces. We prove the strong convergence of the proposed iterative algorithm to the unique solution of a variational inequality, which is the optimality condition for a minimization problem. The results presented in this paper mainly extend the corresponding results announced by Qin et al. [X. Qin, Y. J. Cho, and S. M. Kang, An iterative method for an infinite family of non-expansive mappings in Hilbert spaces, Bull. Malays. Math. Sci. Soc. 32 (2009) 161-171] and many others. end{abstract}
common fixed point
strong convergence
Amenable
semigroup
2012
07
15
369
389
http://bims.iranjournals.ir/article_207_7d5d8ff16fbbbca2e1790a0f9ab74c87.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Recurrent metrics in the geometry of second order differential equations
Mircea
Crasmareanu
Given a pair (semispray $S$, metric $g$) on a tangent bundle, the family of nonlinear connections $N$ such that $g$ is recurrent with respect to $(S, N)$ with a fixed recurrent factor is determined by using the Obata tensors. In particular, we obtain a characterization for a pair $(N, g)$ to be recurrent as well as for the triple $(S, stackrel{c}{N}, g)$ where $stackrel{c}{N}$ is the canonical nonlinear connection of the semispray $S$. Also, the Weyl connection of conformal gauge theories is obtained as a particular case.
Semispray
nonlinear connection
recurrent metric
Obata operators
2011
02
23
391
401
http://bims.iranjournals.ir/article_215_dcd58d4931f7da614e2cbc66aa27cade.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Projective maximal submodules of extending regular modules
E.
Momtahan
We show that a projective maximal submodule of afinitely generated, regular, extending module is a directsummand. Hence, every finitely generated, regular, extendingmodule with projective maximal submodules is semisimple. As aconsequence, we observe that every regular, hereditary, extendingmodule is semisimple. This generalizes and simplifies a result of Dung and Smith. As another consequence, we observe thatevery right continuous ring, whose maximal right ideals areprojective, is semisimple Artinian. This generalizes some resultsof Osofsky and Karamzadeh. We also observe thatfour classes of rings, namely right $aleph_0$-continuous rings,right continuous rings, right $aleph_0$-continuous regular ringsand right continuous regular rings are not axiomatizable.
continuous rings
extending rings
regular
rings
aleph_0-self-injective rings
2012
07
15
403
412
http://bims.iranjournals.ir/article_407_6a4d7f84d031275eb5d254f9f2871b8d.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Finite p-groups with few non-linear irreducible character kernels
Hossein
Doostie
Amin
Saeidi
Abstract. In this paper, we classify all of the ﬁnite p-groups with at most three non linear irreducible character kernels.
Minimal normal subgroups
few character kernels
strong and weak conditions
2012
07
15
413
422
http://bims.iranjournals.ir/article_208_69f56c704b32022bc49cb06797e62448.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Invariance of the barycentric subdivision of a simplicial complex
Rashid
Zaare-Nahandi
In this paper we prove that a simplicial complex is determined uniquely up to isomorphism by its barycentric subdivision as well as its comparability graph. We also put together several algebraic, combinatorial and topological invariants of simplicial complexes.
Simplicial complex
comparability graph
barycentric subdivision
2012
07
15
423
432
http://bims.iranjournals.ir/article_212_de5bc8c7b7b3dc3bfb85ee068f5d21f6.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
On Rickart modules
S
Agayev
S
Halicioglu
A
Harmanci
Let $R$ be an arbitrary ring with identity and $M$ a right $R$-module with $S=$ End$_R(M)$. The module $M$ is called {it Rickart} if for any $fin S$, $r_M(f)=Se$ for some $e^2=ein S$. We prove that some results of principally projective rings and Baer modules can be extended to Rickart modules for this general settings.
Rickart modules
Baer modules
reduced
modules
rigid modules
2012
07
15
433
445
http://bims.iranjournals.ir/article_209_a482f3c0119843e2d96bfda7f6af9907.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Optimal order finite element approximation for a hyperbolic integro-differential equation
Fardin
Saedpanah
Semidiscrete finite element approximation of a hyperbolic type integro-differential equation is studied. The model problem is treated as the wave equation which is perturbed with a memory term. Stability estimates are obtained for a slightly more general problem. These, based on energy method, are used to prove optimal order a priori error estimates.
finite element method
wave equation
integro-differential equation
Stability
a priori error estimate
2012
07
15
447
459
http://bims.iranjournals.ir/article_201_e72a83b9b71c31f92537ef2e58b72810.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Properties of multivalent functions associated with certain integral operator
Jin-Lin
Liu
Let A(p) denote the class of functions which are analytic in the open unit disk U. By making use of certain integral operator,we obtain some interesting properties of multivalent analytic functions.
Multivalent function
analytic function
integral operator
2012
07
15
461
468
http://bims.iranjournals.ir/article_198_05b363674deba2ef06e6925dc08db279.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Applications of epi-retractable modules
Bashishth
Pandeya
Avanish
Chaturvedi
Ashok
Gupta
An R-module M is called epi-retractable if every submodule of MR is a homomorphic image of M. It is shown that if R is a right perfect ring, then every projective slightly compressible module MR is epi-retractable. If R is a Noetherian ring, then every epi-retractable right R-module has direct sum of uniform submodules. If endomorphism ring of a module MR is von-Neumann regular, then M is semi-simple if and only if M is epi-retractable. If R is a quasi Frobenius ring, then R is a right hereditary ring if and only if every injective right R-module is semi-simple. A ring R is semi-simple if and only if R is right hereditary and every epiretractable right R-module is projective. Moreover, a ring R is semi-simple if and only if R is a pri and von-Neumann regular.
Epi-retractable modules
semi-simple rings
Perfect rings
Hereditary rings
von-Numann regular rings
2012
07
15
469
477
http://bims.iranjournals.ir/article_202_388757ddee7a3a67ab050c9a998e2049.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Some vector fields on a riemannian manifold with semi-symmetric metric connection
Füsun
Özen Zengin
Sezgin
Altay Demirbag
S. Aynur
Uysal
Hülya
Bagdatli Yilmaz
In the first part of this paper, some theorems are given for a Riemannian manifold with semi-symmetric metric connection. In the second part of it, some special vector fields, for example, torse-forming vector fields, recurrent vector fields and concurrent vector fields are examined in this manifold. We obtain some properties of this manifold having the vectors mentioned above.
Semi-symmetric metric connection
sectional curvature
conformally flat manifold
pseudo symmetric manifold
concircular
vector field
2012
07
15
479
490
http://bims.iranjournals.ir/article_203_231ecca82cd01017b92531f34000f4d6.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Riordan group approaches in matrix factorizations
Emrah
Kilic
Nese
Omur
Gulfer
Tatar
In this paper, we consider an arbitrary binary polynomial sequence {A_n} and then give a lower triangular matrix representation of this sequence. As main result, we obtain a factorization of the innite generalized Pascal matrix in terms of this new matrix, using a Riordan group approach. Further some interesting results and applications are derived.
Riordan Group
Factorization
Binary Recurrences
Pascal Matrix
2012
07
15
491
506
http://bims.iranjournals.ir/article_205_da5f4f10d7f10a4b73c7db3f21ccb967.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Some homological properties of amalgamated duplication of a ring along an ideal
Mohamed
Chhiti
Najib
Mahdou
In this work, we investigate the transfer of some homological properties from a ring $R$ to its amalgamated duplication along some ideal $I$ of $R$ $Rbowtie I$, and then generate new and original families of rings with these properties.
Amalgamated
Perfect ring
(n
d)-ring
2012
07
15
507
515
http://bims.iranjournals.ir/article_210_485789e3f153661d4d8c1136c73cb0d1.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
A note on the socle of certain types of f-rings
Themba
Dube
For any reduced commutative $f$-ring with identity and bounded inversion, we show that a condition which is obviously necessary for the socle of the ring to coincide with the socle of its bounded part, is actually also sufficient. The condition is that every minimal ideal of the ring consist entirely of bounded elements. It is not too stringent, and is satisfied, for instance, by rings of continuous functions.
frame
function rings
ideal
socle
2012
07
15
517
528
http://bims.iranjournals.ir/article_214_3c1783bf3988903f43f20700e3e575bc.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2012
38
2
Ring structures of mod p equivariant cohomology rings and ring homomorphisms between them
Yanchang
Chen
Yanying
Wang
In this paper, we consider a class of connected oriented (with respect to Z/p) closed G-manifolds with a non-empty finite fixed point set, each of which is G-equivariantly formal, where G = Z/p and p is an odd prime. Using localization theorem and equivariant index, we give an explicit description of the mod p equivariant cohomology ring of such a G-manifold in terms of algebra. This makes it possible to determine the number of equivariant cohomology rings (up to isomorphism) of such 2-dimensional G-manifolds. Moreover, we obtain a description of the ring homomorphism between equivariant cohomology rings of such two G-manifolds induced by a G-equivariant map, and show a characterization of the ring homomorphism.
G-manifold
equivariant index
equivariant cohomology
ring homomorphism
2012
07
15
529
542
http://bims.iranjournals.ir/article_217_d78bd5727580f199e3b327f8189d5d8a.pdf