Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 A lower estimate of harmonic functions 1 7 479 EN Guoshuang Pan Beijing National Day School Lei Qiao Department of Mathematics and Information Science, Henan University of Economics and Law, Zhengzhou, People&#039;s Republic of China Guantie Deng School of Mathematical Science, Beijing Normal University, Beijing, People&#039;s Republic of China. Journal Article 2012 09 10 We shall give a lower estimate of harmonic‎ ‎functions of order greater than one in a half space‎, ‎which‎ <br />‎generalize the result obtained by B‎. ‎Ya‎. ‎Levin in a half plane‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Investigation on the Hermitian matrix expression‎ ‎subject to some consistent equations 9 28 480 EN Xiang Zhang Department of Mathematics, Zunyi Normal College Shanghai Road, Zunyi 563000, P.R. China Journal Article 2012 05 20 In this paper‎, ‎we study the extremal‎ <br />‎ranks and inertias of the Hermitian matrix expression \$\$‎ <br />‎f(X,Y)=C_{4}-B_{4}Y-(B_{4}Y)^{*}-A_{4}XA_{4}^{*},\$\$ where \$C_{4}\$ is‎ <br />‎Hermitian‎, ‎\$*\$ denotes the conjugate transpose‎, ‎\$X\$ and \$Y\$ satisfy‎ <br />‎the following consistent system of matrix equations \$A_{3}Y=C_{3}‎, <br />‎A_{1}X=C_{1},XB_{1}=D_{1},A_{2}XA_{2}^{*}=C_{2},X=X^{*}.\$ As‎ <br />‎consequences‎, ‎we get the necessary and sufficient conditions for the‎ <br />‎above expression \$f(X,Y)\$ to be (semi) positive‎, ‎(semi) negative‎. <br />‎The relations between the Hermitian part of the solution to the‎ <br />‎matrix equation \$A_{3}Y=C_{3}\$ and the Hermitian solution to the‎ <br />‎system of matrix equations‎ <br />‎\$A_{1}X=C_{1},XB_{1}=D_{1},A_{2}XA_{2}^{*}=C_{2}\$ are also‎ <br />‎characterized‎. ‎Moreover‎, ‎we give the necessary and sufficient‎ <br />‎conditions for the solvability to the‎ <br />‎following system of matrix equations‎ <br />‎\$A_{3}Y=C_{3},A_{1}X=C_{1},XB_{1}=D_{1}‎, <br />‎A_{2}XA_{2}^{*}=C_{2},X=X^{*}‎, <br />‎B_{4}Y+(B_{4}Y)^{*}+A_{4}XA_{4}^{*}=C_{4} \$ and provide an‎ <br />‎expression of the general solution to this system‎ <br />‎when it is solvable‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Coupled fixed point results for weakly related mappings in partially ordered metric spaces 29 40 481 EN Naval Singh govt. benazir college, bhopal Reena Jain Technocrats Institute of technology Journal Article 2012 02 15 In the present paper‎, ‎we show the existence of a coupled fixed point for a non-decreasing mapping in partially ordered complete metric space using a partial order induced by an appropriate function \$phi\$‎. ‎We also define the concept of weakly related mappings on an ordered space‎. ‎Moreover common coupled fixed points for two and three weakly related mappings are also proved in the same space‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 ‎A matrix LSQR algorithm for solving constrained linear operator equations 41 53 482 EN Masoud Hajarian Department of Mathematics Faculty of Mathematical Sciences Shahid Beheshti University, G.C., Evin, Tehran 19839 Iran Journal Article 2012 07 09 In this work‎, ‎an iterative method based on a matrix form of LSQR algorithm is constructed for solving the linear operator equation \$mathcal{A}(X)=B\$‎ <br />‎and the minimum Frobenius norm residual problem \$||mathcal{A}(X)-B||_F\$‎ <br />‎where \$Xin mathcal{S}:={Xin textsf{R}^{ntimes n}~|~X=mathcal{G}(X)}\$‎, ‎\$mathcal{F}\$ is the linear operator from \$textsf{R}^{ntimes n}\$ onto \$textsf{R}^{rtimes s}\$‎, <br />‎\$mathcal{G}\$ is a linear self-conjugate involution operator and‎ <br />‎\$Bin textsf{R}^{rtimes s}\$‎. <br />‎Numerical examples are given to verify the efficiency of the constructed method‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Maximal prehomogeneous subspaces on classical groups 55 81 483 EN Xiaoxiang Yu Xuzhou Normal University, P.R.China Dengyin Wang China University of Mining and technology Journal Article 2011 12 09 Suppose \$G\$ is a split connected‎ ‎reductive orthogonal or symplectic group over an infinite field‎ <br />‎\$F,\$ \$P=MN\$ is a maximal parabolic subgroup of \$G,\$ \$frak{n}\$ is‎ <br />‎the Lie algebra of the unipotent radical \$N.\$ Under the adjoint‎ <br />‎action of its stabilizer in \$M,\$ every maximal prehomogeneous‎ <br />‎subspaces of \$frak{n}\$ is determined‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Sequential second derivative general linear methods for stiff systems 83 100 484 EN Ali Karam Ezzeddine University of Tabriz Gholamreza Hojjati University of Tabriz Ali Abdi University of Tabriz Journal Article 2012 09 03 ‎Second derivative general linear methods (SGLMs) as an extension‎ <br />‎of general linear methods (GLMs) have been introduced to improve‎ <br />‎the stability and accuracy properties of GLMs‎. ‎The coefficients of‎ <br />‎SGLMs are given by six matrices‎, ‎instead of four matrices for‎ <br />‎GLMs‎, ‎which are obtained by solving nonlinear systems of order and‎ <br />‎usually Runge--Kutta stability conditions‎. ‎In this paper‎, ‎we‎ <br />‎introduce a technique for construction of an special case of SGLMs‎ <br />‎which decreases the complexity of finding coefficients matrices‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 On the numerical solution of generalized Sylvester matrix equations 101 113 485 EN Amer Kaabi iran Journal Article 2011 11 16 ‎The global FOM and GMRES algorithms are among the effective‎ <br />‎methods to solve Sylvester matrix equations‎. ‎In this paper‎, ‎we‎ <br />‎study these algorithms in the case that the coefficient matrices‎ <br />‎are real symmetric (real symmetric positive definite) and extract‎ <br />‎two CG-type algorithms for solving generalized Sylvester matrix‎ <br />‎equations‎. ‎The proposed methods are iterative projection methods‎ <br />‎onto matrix Krylov subspaces‎. ‎Numerical examples are presented‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 An extension theorem for finite positive measures on surfaces of finite‎ ‎dimensional unit balls in Hilbert spaces 115 124 486 EN Ahmad Reza Soltani Kuwait University and Shiraz University Safieh Mahmoodi Isfahan University of Technology Journal Article 2012 02 24 A consistency criteria is given for a certain class of finite positive <br />measures on the surfaces of the finite dimensional unit balls in a real <br />separable Hilbert space. It is proved, through a Kolmogorov type existence <br />theorem, that the class induces a unique positive measure on the surface of <br />the unit ball in the Hilbert space. As an application, this will naturally <br />accomplish the work of Kanter (1973) on the existence and uniqueness of the <br />spectral measures of finite dimensional stable random vectors to the <br />infinite dimensional ones. The approach presented here is direct and <br />different from the functional analysis approach in Kuelbs (1973), Linde <br />(1983) and the indirect approach of Tortrat (1976) and Dettweiler (1976).
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Embedding measure spaces 125 155 487 EN M.R. Koushesh Isfahan University of Technology Journal Article 2012 10 30 ‎For a given measure space \$(X,{mathscr B},mu)\$ we construct all measure spaces \$(Y,{mathscr C},lambda)\$ in which \$(X,{mathscr B},mu)\$ is embeddable‎. ‎The construction is modeled on the ultrafilter construction of the Stone--v{C}ech compactification of a completely regular topological space‎. ‎Under certain conditions the construction simplifies‎. ‎Examples are given when this simplification occurs‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 A class of Artinian local rings of homogeneous type 157 181 488 EN Leila Sharifan Hakim Sabzevari University, Sabzevar, Iran Journal Article 2012 07 15 ‎Let \$I\$ be an ideal in a regular local ring \$(R,n)\$‎, ‎we will find‎ <br />‎bounds on the first and the last Betti numbers of‎ <br />‎\$(A,m)=(R/I,n/I)\$‎. ‎if \$A\$ is an Artinian ring of the embedding‎ <br />‎codimension \$h\$‎, ‎\$I\$ has the initial degree \$t\$ and \$mu(m^t)=1\$‎, <br />‎we call \$A\$ a {it \$t-\$extended stretched local ring}‎. ‎This class of‎ <br />‎local rings is a natural generalization of the class of stretched local rings studied by Sally‎, ‎Elias and Valla‎. ‎For a \$t-\$extended stretched local ring‎, <br />‎we show that \${h+t-2choose t-1}-h+1leq tau(A)leq {h+t-2choose‎ <br />‎t-1}\$ and \$ {h+t-1choose t}-1 leq mu(I) leq {h+t-1choose t}\$‎. <br />‎Moreover \$tau(A)\$ reaches the upper bound if and only if \$mu(I)\$‎ <br />‎is the maximum value‎. ‎Using these results‎, ‎we show when‎ <br />‎\$beta_i(A)=beta_i(gr_m(A))\$ for each \$igeq 0\$‎. ‎Beside‎, ‎we will‎ <br />‎investigate the rigid behavior of the Betti numbers of \$A\$ in the‎ <br />‎case that \$I\$ has initial degree \$t\$ and \$mu(m^t)=2\$‎. ‎This class‎ <br />‎is a natural generalization of {it almost stretched local rings}‎ <br />‎again studied by Elias and Valla‎. ‎Our research extends several‎ <br />‎results of two papers by Rossi‎, ‎Elias and Valla‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Stochastic bounds for a single server queue with general retrial times 183 198 489 EN Mohamed Boualem University of Bejaia Natalia Djellab University of Annaba Djamil Aïssani University of béjaia Journal Article 2012 06 29 We propose to use a mathematical method based on stochastic comparisons of Markov chains in order to derive performance indice bounds‎. ‎The main goal of this paper is to investigate various monotonicity properties of a single server retrial queue with first-come-first-served (FCFS) orbit and general retrial times using the stochastic ordering techniques‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Existence and uniqueness of common coupled fixed point results via auxiliary functions 199 215 490 EN Sumit Chandok Khalsa College of Engineering & Technology (Punjab Technical University) Erdal Karapinar ATILIM UNIVERSITY Mohammad Saeed Khan Sultan Qaboos University Journal Article 2012 04 01 ‎The purpose of this paper is to establish some coupled coincidence point theorems for mappings having a mixed \$g\$-monotone property in partially ordered metric spaces‎. ‎Also‎, ‎we present a result on the existence and uniqueness of coupled common fixed points‎. ‎The results presented in the paper generalize and extend several well-known results in the literature‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Relative volume comparison theorems in Finsler geometry and their applications 217 234 491 EN Bing Ye Wu Department of Mathematics Minjiang University Journal Article 2012 03 01 We establish some relative volume comparison theorems for extremal volume forms of‎ ‎Finsler manifolds under suitable curvature bounds‎. ‎As their applications‎, ‎we obtain some results on curvature and topology of Finsler manifolds‎. ‎Our results remove the usual assumption on S-curvature that is needed in the literature‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 An eigenvalue study on the sufficient descent property of a‎ ‎modified Polak-Ribière-Polyak conjugate gradient method 235 242 492 EN Saman Babaie-Kafaki Semnan University Journal Article 2012 08 24 ‎Based on an eigenvalue analysis‎, ‎a new proof for the sufficient‎ ‎descent property of the modified Polak-Ribière-Polyak conjugate‎ ‎gradient method proposed by Yu et al‎. ‎is presented‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Various kinds of regular injectivity for \$S\$-posets 243 261 493 EN Leila Shahbaz University of Maragheh Mojgan Mahmoudi Shahid Beheshti University Journal Article 2012 04 18 ‎In this paper some properties of weak regular injectivity for \$S\$-posets‎, <br />‎where \$S\$ is a pomonoid‎, ‎are studied‎. ‎The behaviour‎ <br />‎of different kinds of weak regular injectivity with products‎, ‎coproducts and direct sums is considered‎. ‎Also‎, ‎some‎ <br />‎characterizations of pomonoids over which all \$S\$-posets are of‎ <br />‎some kind of weakly regular injective are obtained‎. ‎Further‎, ‎we‎ <br />‎give some Baer conditions which state the relation among some‎ <br />‎kinds of weak regular injectivity‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 Implicit iteration approximation for a‎ ‎finite family of asymptotically quasi-pseudocontractive type‎ ‎mappings 263 279 494 EN Shuyi Zhang Department of Mathematics, BoHai University Journal Article 2011 12 06 In this paper‎, ‎strong convergence theorems of Ishikawa type implicit iteration‎ <br />‎process with errors for a finite family of asymptotically‎ <br />‎nonexpansive in the intermediate sense and asymptotically‎ <br />‎quasi-pseudocontractive type mappings in normed linear spaces are‎ <br />‎established by using a new analytical method‎, ‎which essentially‎ <br />‎improve and extend some recent results obtained by Yang‎ <br />‎[Convergence theorems of implicit iteration process for‎ <br />‎asymptotically pseudocontractive mappings‎, ‎Bulletin of the Iranian‎ <br />‎Mathematical Society‎, ‎Available Online from 12 April 2011] and‎ <br />‎others‎.
Iranian Mathematical Society (IMS) Bulletin of the Iranian Mathematical Society 1017-060X 40 1 2014 02 01 On the norm of the derived‎ subgroups of all subgroups of a finite group 281 291 495 EN Zhencai Shen LMAM and School of Mathematical Sciences, Peking University, Beijing, 100871, China. Shirong Li Guangxi University Wujie Shi Chongqing University of Arts and Sciences Journal Article 2012 06 30 In this paper‎, ‎we give a complete proof of Theorem 4.1(ii) and a new‎ ‎elementary proof of Theorem 4.1(i) in [Li and Shen‎, ‎On the‎ ‎intersection of the normalizers of the derived subgroups of all‎ <br />‎subgroups of a finite group‎, ‎ J‎. ‎Algebra, ‎323  (2010) 1349--1357]‎. <br />‎In addition‎, ‎we also give a generalization of Baer's Theorem‎.