2019-03-26T23:56:59Z http://bims.iranjournals.ir/?_action=export&rf=summon&issue=52
2012-07-15
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 <br />cone metric spaces, Nonlinear Analysis 72 (2010) 1589-1593] proved <br />some fixed point theorems for weak contractions in cone metric <br />spaces. Weak contractions are generalizations of the Banach's <br />contraction mapping, which have been studied by several authors. In <br />this paper, we introduce the notion of \$f\$-weak contractions and <br />also establish a coincidence and common fixed point result for <br />\$f\$-weak contractions in cone metric spaces. Our result is supported <br />by an example which include and generalize the results of Choudhury <br />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
2012-07-15
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 <br />prove that if \$0_R\$ belongs to \${x_1x_2cdots x_n ;|; <br />x_1,x_2,dots,x_nin X}\$ for every infinite subset \$X\$ of \$R\$, <br />then \$R\$ satisfies the polynomial identity \$x^n=0\$. Also we prove <br />that if \$0_R\$ belongs to \${x_1x_2cdots <br />x_n-x_{n+1} ;|; x_1,x_2,dots,x_n,x_{n+1}in X}\$ for every <br />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
2012-07-15
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 <br />prove the existence of a new family of homotopy elements in the <br />stable homotopy groups of spheres \$pi_{ast}(S)\$ which is <br />represented by \$h_nh_mtilde{beta}_{s+2}in {rm Ext}_A^{s+4, <br />q[p^n+p^m+(s+2)p+(s+1)]+s}(mathbb{Z}_p,mathbb{Z}_p)\$ up to nonzero <br />scalar in the Adams spectral sequence, where \$ngeq m+2>5\$, \$0leq <br />s<br />Ext}_A^{s+2,q[(s+2)p+(s+1)]+s}(mathbb{Z}_p,mathbb{Z}_p)\$ was <br />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
2012-07-15
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 <br />models we find the expected value of the size of a branch in <br />recursive \$k\$-ary trees. We also find the expectation of the <br />number of nodes of a given outdegree in a branch of such <br />trees. trees random recursive trees generalized P'olya urn models 2012 07 15 323 331 http://bims.iranjournals.ir/article_200_0fb18b5d341305095aa3c67a34c101b0.pdf
2012-07-15
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 <br /> unbiased estimator, corresponding to post-stratification approach. Both of these are not location-invariant, but this is ignorable for alternative estimator. <br />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
2012-07-15
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 <br />matrix A is an M-matrix. In the present work, it is proved <br />that the rate of convergence of the Gauss-Seidel method is faster <br />than the mixed-type splitting and AOR (SOR) iterative methods for <br />solving M-matrix linear systems. Furthermore, we improve the rate <br />of convergence of the mixed-type splitting iterative method by <br />applying a preconditioned matrix. Comparison theorems show that <br />the rate of convergence of the preconditioned Gauss-Seidel method <br />is faster than the preconditioned mixed-type splitting and AOR <br />(SOR) iterative methods. Finally, some numerical examples are <br />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
2012-07-15
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} <br />In this paper, we introduce an iterative method for amenable <br />semigroup of non expansive mappings and infinite family of non <br />expansive mappings in the frame work of Hilbert spaces. We prove the <br />strong convergence of the proposed iterative algorithm to the unique <br />solution of a variational inequality, which is the optimality <br />condition for a minimization problem. The results presented in this <br />paper mainly extend the corresponding results announced by Qin et <br />al. [X. Qin, Y. J. Cho, and S. M. Kang, An iterative method for an <br />infinite family of non-expansive mappings in Hilbert spaces, Bull. <br />Malays. Math. Sci. Soc. 32 (2009) 161-171] and many others. <br /> <br />end{abstract} common fixed point strong convergence Amenable semigroup 2012 07 15 369 389 http://bims.iranjournals.ir/article_207_7d5d8ff16fbbbca2e1790a0f9ab74c87.pdf
2011-02-23
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 <br />family of nonlinear connections \$N\$ such that \$g\$ is recurrent <br />with respect to \$(S, N)\$ with a fixed recurrent factor is <br />determined by using the Obata tensors. In particular, we obtain a <br />characterization for a pair \$(N, g)\$ to be recurrent as well as <br />for the triple \$(S, stackrel{c}{N}, g)\$ where \$stackrel{c}{N}\$ <br />is the canonical nonlinear connection of the semispray \$S\$. Also, <br />the Weyl connection of conformal gauge theories is obtained as a particular <br />case. Semispray nonlinear connection recurrent metric Obata operators 2011 02 23 391 401 http://bims.iranjournals.ir/article_215_dcd58d4931f7da614e2cbc66aa27cade.pdf
2012-07-15
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 a<br />finitely generated, regular, extending module is a direct<br />summand. Hence, every finitely generated, regular, extending<br />module with projective maximal submodules is semisimple. As a<br />consequence, we observe that every regular, hereditary, extending<br />module is semisimple. This generalizes and simplifies a result of<br />  Dung and   Smith. As another consequence, we observe that<br />every right continuous ring, whose maximal right ideals are<br />projective, is semisimple Artinian. This generalizes some results<br />of   Osofsky and   Karamzadeh. We also observe that<br />four classes of rings, namely right \$aleph_0\$-continuous rings,<br />right continuous rings, right \$aleph_0\$-continuous regular rings<br />and 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
2012-07-15
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
2012-07-15
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 <br />‎uniquely up to isomorphism by its barycentric subdivision as well as‎ <br />‎its comparability graph‎. ‎We also put together several algebraic‎, <br />‎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
2012-07-15
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 <br />identity and \$M\$ a right \$R\$-module with \$S=\$ End\$_R(M)\$. The <br />module \$M\$ is called {it Rickart} if for any \$fin S\$, <br />\$r_M(f)=Se\$ for some \$e^2=ein S\$. We prove that some results of <br />principally projective rings and Baer modules can be extended to <br />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
2012-07-15
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 <br />‎integro-differential equation is studied. The model problem is‎ <br />‎treated as the wave equation which is perturbed with a memory term.‎ <br />‎Stability estimates are obtained for a slightly more general problem.‎ <br />‎These, based on energy method, are used to prove optimal order‎ <br />‎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
2012-07-15
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
2012-07-15
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
2012-07-15
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
2012-07-15
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 in nite generalized Pascal matrix in terms of this new matrix, <br />using a Riordan group approach. Further some interesting results <br />and applications are derived. Riordan Group Factorization Binary Recurrences Pascal Matrix 2012 07 15 491 506 http://bims.iranjournals.ir/article_205_da5f4f10d7f10a4b73c7db3f21ccb967.pdf
2012-07-15
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 <br />properties from a ring \$R\$ to its amalgamated duplication along <br />some ideal \$I\$ of \$R\$ \$Rbowtie I\$, and then generate new and <br />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
2012-07-15
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 <br />inversion, we show that a condition which is obviously necessary for <br />the socle of the ring to coincide with the socle of its bounded <br />part, is actually also sufficient. The condition is that every <br />minimal ideal of the ring consist entirely of bounded elements. It <br />is not too stringent, and is satisfied, for instance, by rings of <br />continuous functions. frame function rings ideal socle 2012 07 15 517 528 http://bims.iranjournals.ir/article_214_3c1783bf3988903f43f20700e3e575bc.pdf
2012-07-15
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