ORIGINAL_ARTICLE On the spectra of some matrices derived from two quadratic matrices begin{abstract} The relations between the spectrum of the matrix \$Q+R\$ and the spectra of the matrices \$(gamma + delta)Q+(alpha + beta)R-QR-RQ\$, \$QR-RQ\$, \$alpha beta R-QRQ\$, \$alpha RQR-(QR)^{2}\$, and \$beta R-QR\$ have been given on condition that the matrix \$Q+R\$ is diagonalizable, where \$Q\$, \$R\$ are \${alpha, beta}\$-quadratic matrix and \${gamma, delta}\$-quadratic matrix, respectively, of order \$n\$. end{abstract} http://bims.iranjournals.ir/article_337_6b4319d54520d67fc847630c7c2cac10.pdf 2013-05-01T11:23:20 2019-06-17T11:23:20 225 238 Quadratic matrix idempotent matrix spectrum linear combination diagonalization H. Ozdemir hozdemir@sakarya.edu.tr true 1 Department of Mathematics, University of Sakarya, TR54187, Sakarya, Turkey Department of Mathematics, University of Sakarya, TR54187, Sakarya, Turkey Department of Mathematics, University of Sakarya, TR54187, Sakarya, Turkey LEAD_AUTHOR T. Petik petiktugba@hotmail.com true 2 Department of Mathematics, University of Sakarya,TR54187, Sakarya, Turkey Department of Mathematics, University of Sakarya,TR54187, Sakarya, Turkey Department of Mathematics, University of Sakarya,TR54187, Sakarya, Turkey AUTHOR
ORIGINAL_ARTICLE The least-square bisymmetric solution to a quaternion matrix equation with applications In this paper, we derive the necessary and sufficient conditions for the quaternion matrix equation XA=B to have the least-square bisymmetric solution and give the expression of such solution when the solvability conditions are met. Futhermore, we consider the maximal and minimal inertias of the least-square bisymmetric solution to this equation. As applications, we derive sufficient and necessary conditions for XA=B to have the positive (nonnegative) definite least-square bisymmetric solution and the maximal (minimal) least-square bisymmetric solution. http://bims.iranjournals.ir/article_340_5bfe11787a82c95ca80797926f05c97f.pdf 2013-05-15T11:23:20 2019-06-17T11:23:20 239 257 Quaternion matrix equation bisymmetric matrix least-square solution Inertia Q. Wang wqw858@yahoo.com.cn true 1 Department of Mathematics, Shanghai University Department of Mathematics, Shanghai University Department of Mathematics, Shanghai University LEAD_AUTHOR G. Yu yuguihai@126.com true 2 Department of Mathematics, Shanghai University Department of Mathematics, Shanghai University Department of Mathematics, Shanghai University AUTHOR
ORIGINAL_ARTICLE Optimal convex combinations bounds of centrodial and harmonic means for logarithmic and identric means We find the greatest values \$alpha_{1} \$ and \$alpha_{2} \$, and the least values \$beta_{1} \$ and \$beta_{2} \$ such that the inequalities \$alpha_{1} C(a,b)+(1-alpha_{1} )H(a,b)<L(a,b)<beta_{1} C(a,b)+(1-beta_{1} )H(a,b)\$ and \$alpha_{2} C(a,b)+(1-alpha_{2}) H(a,b)<I(a,b)<beta_{2} C(a,b)+(1-beta_{2} )H(a,b)\$ hold for all \$a,b>0\$ with \$aneq b\$. Here, \$C(a,b)\$, \$H(a,b)\$, \$L(a,b)\$, and \$I(a,b)\$ are the centroidal, harmonic, logarithmic, and identric means of two positive numbers \$a\$ and \$b\$, respectively. http://bims.iranjournals.ir/article_411_ce7ebf9563324f84f8dface04487e196.pdf 2013-05-15T11:23:20 2019-06-17T11:23:20 259 269 logarithmic mean identric mean centroidal mean harmonic mean Y. Chu chuyuming@hutc.zj.cn true 1 Huzhou Teachers College Huzhou Teachers College Huzhou Teachers College LEAD_AUTHOR S. Hou houshouwei2008@163.com true 2 Huzhou Teachers College Huzhou Teachers College Huzhou Teachers College AUTHOR W. Xia xwf212@hutc.zj.cn true 3 Huzhou Teachers College Huzhou Teachers College Huzhou Teachers College AUTHOR
ORIGINAL_ARTICLE Finite groups with three relative commutativity degrees ‎‎For a finite group \$G\$ and a subgroup \$H\$ of \$G\$‎, ‎the relative commutativity degree of \$H\$ in \$G\$‎, ‎denoted by \$d(H,G)\$‎, ‎is the probability that an element of \$H\$ commutes with an element of \$G\$‎. ‎Let \$mathcal{D}(G)={d(H,G):Hleq G}\$ be the set of all relative commutativity degrees of subgroups of \$G\$‎. ‎It is shown that a finite group \$G\$ admits three relative commutativity degrees if and only if \$G/Z(G)\$ is a non-cyclic group of order \$pq\$‎, ‎where \$p\$ and \$q\$ are primes‎. ‎Moreover‎, ‎we determine all the relative commutativity degrees of some known groups‎. http://bims.iranjournals.ir/article_412_c7a8a12e199ac1ff4482cfd330bf4466.pdf 2013-05-15T11:23:20 2019-06-17T11:23:20 271 280 Commutativity degree‎ ‎relative commutativity degree‎ ‎isoclinism‎ ‎relative isoclinism R. Barzegar ‎ro.gbps@gmail.com true 1 Ferdowsi University of Mashhad Ferdowsi University of Mashhad Ferdowsi University of Mashhad AUTHOR A. Erfanian erfanian@math.um.ac.ir true 2 Ferdowsi University of Mashhad Ferdowsi University of Mashhad Ferdowsi University of Mashhad LEAD_AUTHOR M. Farrokhi D. G. m.farrokhi.d.g@gmail.com true 3 Ferdowsi University of Mashhad Ferdowsi University of Mashhad Ferdowsi University of Mashhad AUTHOR
ORIGINAL_ARTICLE Gorenstein flat and Gorenstein injective dimensions of simple modules Let R be a right GF-closed ring with finite left and right Gorenstein global dimension. We prove that if I is an ideal of R such that R/I is a semi-simple ring, then the Gorensntein flat dimensnion of R/I as a right R-module and the Gorensntein injective dimensnnion of R/I as a left R-module are identical. In particular, we show that for a simple module S over a commutative Gorensntein ring R, the Gorenstein flat dimension of S equals to the Gorenstein injective dimension of S. http://bims.iranjournals.ir/article_413_0c2096907897563917352df573b7123b.pdf 2013-05-15T11:23:20 2019-06-17T11:23:20 281 287 Gorenstein flat dimension Gorenstein injective dimension simple module A. Xu xuaimin88888@126.com true 1 Department of Mathematics, Nanjing University Department of Mathematics, Nanjing University Department of Mathematics, Nanjing University AUTHOR X. Yan yanxg1109@sina.cn true 2 School of Mathematics & Information Technology, Nanjing Xiaozhuang University School of Mathematics & Information Technology, Nanjing Xiaozhuang University School of Mathematics & Information Technology, Nanjing Xiaozhuang University LEAD_AUTHOR
ORIGINAL_ARTICLE Quasirecognition by the prime graph of L_3(q) where 3 < q < 100 Let \$G\$ be a finite group. We construct the prime graph of \$ G \$,which is denoted by \$ Gamma(G) \$ as follows: the vertex set of thisgraph is the prime divisors of \$ |G| \$ and two distinct vertices \$ p\$ and \$ q \$ are joined by an edge if and only if \$ G \$ contains anelement of order \$ pq \$.In this paper, we determine finite groups \$ G \$ with \$ Gamma(G) =Gamma(L_3(q)) \$, \$2 leq q < 100 \$ and prove that if \$ q neq 2, 3\$, then \$L_3(q) \$ is quasirecognizable by prime graph, i.e., if \$G\$is a finite group with the same prime graph as the finite simplegroup \$L_3(q)\$, then \$G\$ has a unique non-Abelian composition factorisomorphic to \$L_3(q)\$. As a consequence of our results we provethat the simple group \$L_{3}(4)\$ is recognizable and the simplegroups \$L_{3}(7)\$ and \$L_{3}(9)\$ are \$2-\$recognizable by the primegraph. http://bims.iranjournals.ir/article_414_abb286fd32fe231f0647dce9cdb1cae2.pdf 2013-05-01T11:23:20 2019-06-17T11:23:20 289 305 Prime graph element order simple group linear group S. S. Salehi Amiri salehisss@yahoo.com true 1 Islamic Azad University Islamic Azad University Islamic Azad University AUTHOR A. Khalili Asboei alirezakhas@gmail.com true 2 Islamic Azad University Islamic Azad University Islamic Azad University AUTHOR A. Iranmanesh iranmana@yahoo.com true 3 Tarbiat Modares University Tarbiat Modares University Tarbiat Modares University LEAD_AUTHOR A. Tehranian tehranian1340@yahoo.com true 4 Islamic Azad University Islamic Azad University Islamic Azad University AUTHOR
ORIGINAL_ARTICLE Existence of positive solutions for a boundary value problem of a nonlinear fractional differential equation This paper presents conditions for the existence and multiplicity of positive solutions for a boundary value problem of a nonlinear fractional differential equation. We show that it has at least one or two positive solutions. The main tool is Krasnosel'skii fixed point theorem on cone and fixed point index theory. http://bims.iranjournals.ir/article_415_bcc9076ae61d66e52701f70a718d0c42.pdf 2013-05-15T11:23:20 2019-06-17T11:23:20 307 323 Caputo derivative cone fixed point theorem Fractional differential equation positive solutions F. Torres francisco.torres@uda.cl true 1 Departamento de Matematica Universidad de Atacama Departamento de Matematica Universidad de Atacama Departamento de Matematica Universidad de Atacama LEAD_AUTHOR
ORIGINAL_ARTICLE On H-cofinitely supplemented modules A module \$M\$ is called \$emph{H}\$-cofinitely supplemented if for every cofinite submodule \$E\$ (i.e. \$M/E\$ is finitely generated) of \$M\$ there exists a direct summand \$D\$ of \$M\$ such that \$M = E + X\$ holds if and only if \$M = D + X\$, for every submodule \$X\$ of \$M\$. In this paper we study factors, direct summands and direct sums of \$emph{H}\$-cofinitely supplemented modules. Let \$M\$ be an \$emph{H}\$-cofinitely supplemented module and let \$N leq M\$ be a submodule. Suppose that for every direct summand \$K\$ of \$M\$, \$(N + K)/N\$ lies above a direct summand of \$M/N\$. Then \$M/N\$ is \$emph{H}\$-cofinitely supplemented. Let \$M\$ be an \$emph{H}\$-cofinitely supplemented module. Let \$N\$ be a direct summand of \$M\$. Suppose that for every direct summand \$K\$ of \$M\$ with \$M=N+K\$, \$Ncap K\$ is also a direct summand of \$M\$. Then \$N\$ is \$emph{H}\$-cofinitely supplemented. Let \$M = M_{1} oplus M_{2}\$. If \$M_{1}\$ is radical \$M_{2}\$-projective (or \$M_{2}\$ is radical \$M_{1}\$-projective) and \$M_{1}\$ and \$M_{2}\$ are \$emph{H}\$-cofinitely supplemented, then \$M\$ is \$emph{H}\$-cofinitely supplemented http://bims.iranjournals.ir/article_416_a39509657a78fc90c5d27db44e1ed1d3.pdf 2013-05-15T11:23:20 2019-06-17T11:23:20 325 346 H-supplemented module H-cofinitely supplemented module radical-projective module Y. Talebi talebi@umz.ac.ir true 1 University of Mazandaran, Iran University of Mazandaran, Iran University of Mazandaran, Iran AUTHOR R. Tribak tribak12@yahoo.com true 2 University of Tetouan University of Tetouan University of Tetouan LEAD_AUTHOR A. Moniri Hamzekolaei a.monirih@umz.ac.ir true 3 Univeristy of Mazandaran, Iran Univeristy of Mazandaran, Iran Univeristy of Mazandaran, Iran AUTHOR
ORIGINAL_ARTICLE Hyers-Ulam-Rassias stability of n-Jordan *-homomorphisms on C*-algebras In this paper, we introduce n-jordan homomorphisms and n-jordan *-homomorphisms and Also investigate the Hyers-Ulam-Rassiasstability of n-jordan *-homomorphisms on C*-algebras. http://bims.iranjournals.ir/article_417_c380aae386a841b43bbf3cd5bd085049.pdf 2013-05-15T11:23:20 2019-06-17T11:23:20 347 353 Hyers-Ulam-Rassias stability n-Jordan *-homomorphism n-jordan homomorphism C*-algebra Sh. Ghaffary Ghaleh shahram.ghaffary@gmail.com true 1 Department of Mathematics, Payame Noor University of Zahedan Branch, Zahedan, Iran Department of Mathematics, Payame Noor University of Zahedan Branch, Zahedan, Iran Department of Mathematics, Payame Noor University of Zahedan Branch, Zahedan, Iran LEAD_AUTHOR Kh. Ghasemi khatere.ghasemi@gmail.com true 2 Department of Mathematics, Payame Noor University of Khash Branch, Khash, Iran Department of Mathematics, Payame Noor University of Khash Branch, Khash, Iran Department of Mathematics, Payame Noor University of Khash Branch, Khash, Iran AUTHOR
ORIGINAL_ARTICLE Ore extensions of skew \$pi\$-Armendariz rings For a ring endomorphism \$alpha\$ and an \$alpha\$-derivation \$delta\$, we introduce a concept, so called skew \$pi\$-Armendariz ring, that is a generalization of both \$pi\$-Armendariz rings, and \$(alpha,delta)\$-compatible skew Armendariz rings. We first observe the basic properties of skew \$pi\$-Armendariz rings, and extend the class of skew \$pi\$-Armendariz rings through various ring extensions. We next show that all \$(alpha,delta)\$-compatible \$NI\$ rings are skew \$pi\$-Armendariz, and if a ring \$R\$ is an \$(alpha,delta)\$-compatible \$2\$-\$primal\$ ring, then the polynomial ring \$R[x]\$ is skew \$pi\$-Armendariz. http://bims.iranjournals.ir/article_315_670f68e3782d06daa57d42c7aaf944da.pdf 2013-05-15T11:23:20 2019-06-17T11:23:20 355 368 skew Armendariz ring skew \$pi\$-Armendariz ring \$pi\$-Armendariz ring O. Lunqun ouyanglqtxy@163.com true 1 Department of Mathematics, Hunan University of Science and Technology, Xiangtan, Hunan 411201, P.R. China Department of Mathematics, Hunan University of Science and Technology, Xiangtan, Hunan 411201, P.R. China Department of Mathematics, Hunan University of Science and Technology, Xiangtan, Hunan 411201, P.R. China LEAD_AUTHOR L. Jingwang jwliu64@yohoo.com.cn true 2 Department of Mathematics, Hunan University of Science and Technology Xiangtan, Hunan 411201, P. R. China Department of Mathematics, Hunan University of Science and Technology Xiangtan, Hunan 411201, P. R. China Department of Mathematics, Hunan University of Science and Technology Xiangtan, Hunan 411201, P. R. China AUTHOR X. Yueming xymls999@126.com true 3 Department of Mathematics and Applied Mathematics, Huaihua University, Huaihua, 418000, P. R. China Department of Mathematics and Applied Mathematics, Huaihua University, Huaihua, 418000, P. R. China Department of Mathematics and Applied Mathematics, Huaihua University, Huaihua, 418000, P. R. China AUTHOR
ORIGINAL_ARTICLE On the fixed point theorems in generalized weakly contractive mappings on partial metric spaces In this paper, we prove a fi xed point theorem for a pair of generalized weakly contractive mappings in complete partial metric spaces. The theorems presented are generalizations of very recent fixed point theorems due to Abdeljawad, Karapinar and Tas. To emphasize the very general nature of these results, we illustrate an example. http://bims.iranjournals.ir/article_344_9cee21f500eec7a4df3245b5b9a8734e.pdf 2013-05-01T11:23:20 2019-06-17T11:23:20 369 381 fixed point theorems partial metric spaces weakly contractive mappings K. Chi chidhv@gmail.com true 1 Vinh University Vinh University Vinh University AUTHOR E. Karapinar erdalkarapinar@yahoo.com true 2 ATILIM UNIVERSITY ATILIM UNIVERSITY ATILIM UNIVERSITY LEAD_AUTHOR T. Thanh cesurakar@gmail.com true 3 Vinh University Vinh University Vinh University AUTHOR