ORIGINAL_ARTICLE
A lower estimate of harmonic functions
We shall give a lower estimate of harmonic functions of order greater than one in a half space, which generalize the result obtained by B. Ya. Levin in a half plane.
http://bims.iranjournals.ir/article_479_2cdf12321f02f3726af6042859a49ca3.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
1
7
Lower estimate
Harmonic function
Half space
Guoshuang
Pan
gsp1979@163.com
true
1
Beijing National Day School
Beijing National Day School
Beijing National Day School
LEAD_AUTHOR
Lei
Qiao
qiaocqu@163.com
true
2
Department of Mathematics and Information Science, Henan University of Economics and Law, Zhengzhou, People's Republic of China
Department of Mathematics and Information Science, Henan University of Economics and Law, Zhengzhou, People's Republic of China
Department of Mathematics and Information Science, Henan University of Economics and Law, Zhengzhou, People's Republic of China
AUTHOR
Guantie
Deng
denggt@bnu.edu.cn
true
3
School of Mathematical
Science, Beijing Normal University, Beijing, People's Republic of China.
School of Mathematical
Science, Beijing Normal University, Beijing, People's Republic of China.
School of Mathematical
Science, Beijing Normal University, Beijing, People's Republic of China.
AUTHOR
ORIGINAL_ARTICLE
Investigation on the Hermitian matrix expression subject to some consistent equations
In this paper, we study the extremal ranks and inertias of the Hermitian matrix expression $$ f(X,Y)=C_{4}-B_{4}Y-(B_{4}Y)^{*}-A_{4}XA_{4}^{*},$$ where $C_{4}$ is Hermitian, $*$ denotes the conjugate transpose, $X$ and $Y$ satisfy the following consistent system of matrix equations $A_{3}Y=C_{3}, A_{1}X=C_{1},XB_{1}=D_{1},A_{2}XA_{2}^{*}=C_{2},X=X^{*}.$ As consequences, we get the necessary and sufficient conditions for the above expression $f(X,Y)$ to be (semi) positive, (semi) negative. The relations between the Hermitian part of the solution to the matrix equation $A_{3}Y=C_{3}$ and the Hermitian solution to the system of matrix equations $A_{1}X=C_{1},XB_{1}=D_{1},A_{2}XA_{2}^{*}=C_{2}$ are also characterized. Moreover, we give the necessary and sufficient conditions for the solvability to the following system of matrix equations $A_{3}Y=C_{3},A_{1}X=C_{1},XB_{1}=D_{1}, A_{2}XA_{2}^{*}=C_{2},X=X^{*}, B_{4}Y+(B_{4}Y)^{*}+A_{4}XA_{4}^{*}=C_{4} $ and provide an expression of the general solution to this system when it is solvable.
http://bims.iranjournals.ir/article_480_368a4a67459524d7aa8a44355b07f8d1.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
9
28
Linear matrix equation
Moore-Penrose inverse
rank
Inertia
Xiang
Zhang
zxjnsc@163.com
true
1
Department of Mathematics, Zunyi Normal College Shanghai Road, Zunyi
563000, P.R. China
Department of Mathematics, Zunyi Normal College Shanghai Road, Zunyi
563000, P.R. China
Department of Mathematics, Zunyi Normal College Shanghai Road, Zunyi
563000, P.R. China
LEAD_AUTHOR
ORIGINAL_ARTICLE
Coupled fixed point results for weakly related mappings in partially ordered metric spaces
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.
http://bims.iranjournals.ir/article_481_4e6a03a572aeff155f37a395d5757e77.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
29
40
Coupled fixed point
common coupled fixed point
partially ordered space
weakly related mappings
Naval
Singh
drsinghnaval@gmail.com
true
1
govt. benazir college, bhopal
govt. benazir college, bhopal
govt. benazir college, bhopal
AUTHOR
Reena
Jain
reenakhatod@gmail.com
true
2
Technocrats Institute of technology
Technocrats Institute of technology
Technocrats Institute of technology
LEAD_AUTHOR
ORIGINAL_ARTICLE
A matrix LSQR algorithm for solving constrained linear operator equations
In this work, an iterative method based on a matrix form of LSQR algorithm is constructed for solving the linear operator equation $mathcal{A}(X)=B$ and the minimum Frobenius norm residual problem $||mathcal{A}(X)-B||_F$ 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 $textsf{R}^{rtimes s}$, $mathcal{G}$ is a linear self-conjugate involution operator and $Bin textsf{R}^{rtimes s}$. Numerical examples are given to verify the efficiency of the constructed method.
http://bims.iranjournals.ir/article_482_84ccde0152b76da6ba408ddf2be03cef.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
41
53
Iterative method
Bidiagonalization procedure
Linear operator equation
Masoud
Hajarian
mhajarian@aut.ac.ir
true
1
Department of Mathematics
Faculty of Mathematical Sciences
Shahid Beheshti University, G.C.,
Evin, Tehran 19839
Iran
Department of Mathematics
Faculty of Mathematical Sciences
Shahid Beheshti University, G.C.,
Evin, Tehran 19839
Iran
Department of Mathematics
Faculty of Mathematical Sciences
Shahid Beheshti University, G.C.,
Evin, Tehran 19839
Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
Maximal prehomogeneous subspaces on classical groups
Suppose $G$ is a split connected reductive orthogonal or symplectic group over an infinite field $F,$ $P=MN$ is a maximal parabolic subgroup of $G,$ $frak{n}$ is the Lie algebra of the unipotent radical $N.$ Under the adjoint action of its stabilizer in $M,$ every maximal prehomogeneous subspaces of $frak{n}$ is determined.
http://bims.iranjournals.ir/article_483_e3bd93459034ea5c23b49e16867e543d.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
55
81
prehomogeneous space
adjoint action
orthogonal
symplectic
orbit
Xiaoxiang
Yu
carston123@126.com
true
1
Xuzhou Normal University,
P.R.China
Xuzhou Normal University,
P.R.China
Xuzhou Normal University,
P.R.China
LEAD_AUTHOR
Dengyin
Wang
wdengyin@126.com
true
2
China University of Mining and technology
China University of Mining and technology
China University of Mining and technology
AUTHOR
ORIGINAL_ARTICLE
Sequential second derivative general linear methods for stiff systems
Second derivative general linear methods (SGLMs) as an extension of general linear methods (GLMs) have been introduced to improve the stability and accuracy properties of GLMs. The coefficients of SGLMs are given by six matrices, instead of four matrices for GLMs, which are obtained by solving nonlinear systems of order and usually Runge--Kutta stability conditions. In this paper, we introduce a technique for construction of an special case of SGLMs which decreases the complexity of finding coefficients matrices.
http://bims.iranjournals.ir/article_484_e8bcd98926dd7174a8892e92e75c9438.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
83
100
General linear methods
Two--derivative methods
ordinary differential equation
Order conditions
A- and
L-stability
Ali
Ezzeddine
aliezz@tabrizu.ac.ir
true
1
University of Tabriz
University of Tabriz
University of Tabriz
AUTHOR
Gholamreza
Hojjati
ghojjati@yahoo.com
true
2
University of Tabriz
University of Tabriz
University of Tabriz
LEAD_AUTHOR
Ali
Abdi
a_abdi@tabrizu.ac.ir
true
3
University of Tabriz
University of Tabriz
University of Tabriz
AUTHOR
ORIGINAL_ARTICLE
On the numerical solution of generalized Sylvester matrix equations
The global FOM and GMRES algorithms are among the effective methods to solve Sylvester matrix equations. In this paper, we study these algorithms in the case that the coefficient matrices are real symmetric (real symmetric positive definite) and extract two CG-type algorithms for solving generalized Sylvester matrix equations. The proposed methods are iterative projection methods onto matrix Krylov subspaces. Numerical examples are presented.
http://bims.iranjournals.ir/article_485_1ba2c57bb65ad0afe866e7641b82604c.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
101
113
Generalized Sylvester matrix equations
Matrix Krylove subspace
Global gmres algorithm
Amer
Kaabi
kaabi_amer@kmsu.ac.ir
true
1
iran
iran
iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
An extension theorem for finite positive measures on surfaces of finite dimensional unit balls in Hilbert spaces
A consistency criteria is given for a certain class of finite positive measures on the surfaces of the finite dimensional unit balls in a real separable Hilbert space. It is proved, through a Kolmogorov type existence theorem, that the class induces a unique positive measure on the surface of the unit ball in the Hilbert space. As an application, this will naturally accomplish the work of Kanter (1973) on the existence and uniqueness of the spectral measures of finite dimensional stable random vectors to the infinite dimensional ones. The approach presented here is direct and different from the functional analysis approach in Kuelbs (1973), Linde (1983) and the indirect approach of Tortrat (1976) and Dettweiler (1976).
http://bims.iranjournals.ir/article_486_e2f1c822857f6f622874900911e812f6.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
115
124
Extension Theorem
Separable Hilbert space
Finite Measures on
Surfaces of the Unit Balls
Stable distribution
Spectral measure
Ahmad Reza
Soltani
soltani@kuc01.kuniv.edu.kw
true
1
Kuwait University and Shiraz University
Kuwait University and Shiraz University
Kuwait University and Shiraz University
AUTHOR
Safieh
Mahmoodi
mahmoodi@cc.iut.ac.ir
true
2
Isfahan University of Technology
Isfahan University of Technology
Isfahan University of Technology
LEAD_AUTHOR
ORIGINAL_ARTICLE
Embedding measure spaces
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.
http://bims.iranjournals.ir/article_487_5d8ac1365f2e598525cbe53890ad515d.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
125
155
Ultrafilter
thick subset
set of full outer measure
topological measure space
Baire measure
Stone--v{C}ech compactification
realcompactification
M.R.
Koushesh
koushesh@cc.iut.ac.ir
true
1
Isfahan University of Technology
Isfahan University of Technology
Isfahan University of Technology
LEAD_AUTHOR
ORIGINAL_ARTICLE
A class of Artinian local rings of homogeneous type
Let $I$ be an ideal in a regular local ring $(R,n)$, we will find bounds on the first and the last Betti numbers of $(A,m)=(R/I,n/I)$. if $A$ is an Artinian ring of the embedding codimension $h$, $I$ has the initial degree $t$ and $mu(m^t)=1$, we call $A$ a {it $t-$extended stretched local ring}. This class of 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, we show that ${h+t-2choose t-1}-h+1leq tau(A)leq {h+t-2choose t-1}$ and $ {h+t-1choose t}-1 leq mu(I) leq {h+t-1choose t}$. Moreover $tau(A)$ reaches the upper bound if and only if $mu(I)$ is the maximum value. Using these results, we show when $beta_i(A)=beta_i(gr_m(A))$ for each $igeq 0$. Beside, we will investigate the rigid behavior of the Betti numbers of $A$ in the case that $I$ has initial degree $t$ and $mu(m^t)=2$. This class is a natural generalization of {it almost stretched local rings} again studied by Elias and Valla. Our research extends several results of two papers by Rossi, Elias and Valla.
http://bims.iranjournals.ir/article_488_46a770dbf68f66aa47bf6509eded267f.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
157
181
artinian rings
Hilbert function
number of
generators
Cohen-Macaulay type
Leila
Sharifan
leilasharifan@gmail.com
true
1
Hakim Sabzevari University, Sabzevar, Iran
Hakim Sabzevari University, Sabzevar, Iran
Hakim Sabzevari University, Sabzevar, Iran
LEAD_AUTHOR
ORIGINAL_ARTICLE
Stochastic bounds for a single server queue with general retrial times
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.
http://bims.iranjournals.ir/article_489_d8f721e663cfe851a582b1a8bde9e06e.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
183
198
Retrial queues
Markov chain
stochastic bounds
Monotonicity
ageing distributions
Mohamed
Boualem
robertt15dz@yahoo.fr
true
1
University of Bejaia
University of Bejaia
University of Bejaia
LEAD_AUTHOR
Natalia
Djellab
djellab@yahoo.fr
true
2
University of Annaba
University of Annaba
University of Annaba
AUTHOR
Djamil
Aïssani
lamos_bejaia@hotmail.com
true
3
University of béjaia
University of béjaia
University of béjaia
AUTHOR
ORIGINAL_ARTICLE
Existence and uniqueness of common coupled fixed point results via auxiliary functions
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.
http://bims.iranjournals.ir/article_490_ff5cc3dca3e0121e2ecee853eea3a1ed.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
199
215
Coupled coincidence
point
ordered sets
Coupled fixed point
mixed monotone property
Sumit
Chandok
chandhok.sumit@gmail.com
true
1
Khalsa College of Engineering & Technology (Punjab Technical University)
Khalsa College of Engineering & Technology (Punjab Technical University)
Khalsa College of Engineering & Technology (Punjab Technical University)
AUTHOR
Erdal
Karapinar
erdalkarapinar@yahoo.com
true
2
ATILIM UNIVERSITY
ATILIM UNIVERSITY
ATILIM UNIVERSITY
LEAD_AUTHOR
Mohammad Saeed
Khan
mohammad@squ.edu.om
true
3
Sultan Qaboos University
Sultan Qaboos University
Sultan Qaboos University
AUTHOR
ORIGINAL_ARTICLE
Relative volume comparison theorems in Finsler geometry and their applications
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.
http://bims.iranjournals.ir/article_491_a6a751d01b68cc3adc7d1c13f8010dc7.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
217
234
extreme volume form
Finsler manifold
Gromov pre-compactness
first Betti number
fundamental group
Bing Ye
Wu
569405943@qq.com
true
1
Department of Mathematics
Minjiang University
Department of Mathematics
Minjiang University
Department of Mathematics
Minjiang University
LEAD_AUTHOR
ORIGINAL_ARTICLE
An eigenvalue study on the sufficient descent property of a modified Polak-Ribière-Polyak conjugate gradient method
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.
http://bims.iranjournals.ir/article_492_329f84fb9fa3da162a1ea3377a2c650e.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
235
242
unconstrained optimization
Conjugate gradient algorithm
Sufficient descent condition
Eigenvalue
Saman
Babaie-Kafaki
sbk@semnan.ac.ir
true
1
Semnan University
Semnan University
Semnan University
LEAD_AUTHOR
ORIGINAL_ARTICLE
Various kinds of regular injectivity for $S$-posets
In this paper some properties of weak regular injectivity for $S$-posets, where $S$ is a pomonoid, are studied. The behaviour of different kinds of weak regular injectivity with products, coproducts and direct sums is considered. Also, some characterizations of pomonoids over which all $S$-posets are of some kind of weakly regular injective are obtained. Further, we give some Baer conditions which state the relation among some kinds of weak regular injectivity.
http://bims.iranjournals.ir/article_493_ffd4d4411686956bba1a760f8c5969b5.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
243
261
$S$-poset
regular injective
weakly regular injective
Leila
Shahbaz
leilashahbaz@yahoo.com
true
1
University of Maragheh
University of Maragheh
University of Maragheh
LEAD_AUTHOR
Mojgan
Mahmoudi
mojganmahmoudi@yahoo.com
true
2
Shahid Beheshti University
Shahid Beheshti University
Shahid Beheshti University
AUTHOR
ORIGINAL_ARTICLE
Implicit iteration approximation for a finite family of asymptotically quasi-pseudocontractive type mappings
In this paper, strong convergence theorems of Ishikawa type implicit iteration process with errors for a finite family of asymptotically nonexpansive in the intermediate sense and asymptotically quasi-pseudocontractive type mappings in normed linear spaces are established by using a new analytical method, which essentially improve and extend some recent results obtained by Yang [Convergence theorems of implicit iteration process for asymptotically pseudocontractive mappings, Bulletin of the Iranian Mathematical Society, Available Online from 12 April 2011] and others.
http://bims.iranjournals.ir/article_494_3783b5bd681d2f9f26ad8b170b0d7dba.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
263
279
Normed linear spaces
implicit iteration process
asymptotically quasi-pseudocontractive type mappings
nonexpansive mappings
Shuyi
Zhang
jzzhangshuyi@126.com
true
1
Department of Mathematics, BoHai University
Department of Mathematics, BoHai University
Department of Mathematics, BoHai University
LEAD_AUTHOR
ORIGINAL_ARTICLE
On the norm of the derived subgroups of all subgroups of a finite group
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 subgroups of a finite group, J. Algebra, 323 (2010) 1349--1357]. In addition, we also give a generalization of Baer's Theorem.
http://bims.iranjournals.ir/article_495_6dc0df68eafac1db15b433778ac7a5c1.pdf
2014-02-01T11:23:20
2018-11-15T11:23:20
281
291
Derived subgroup
solvable group
nilpotency class
Fitting length
Zhencai
Shen
zhencai688@sina.com
true
1
LMAM and School of Mathematical Sciences, Peking
University,
Beijing, 100871, China.
LMAM and School of Mathematical Sciences, Peking
University,
Beijing, 100871, China.
LMAM and School of Mathematical Sciences, Peking
University,
Beijing, 100871, China.
AUTHOR
Shirong
Li
shirong@sina.com
true
2
Guangxi University
Guangxi University
Guangxi University
AUTHOR
Wujie
Shi
shiwujie@outlook.com
true
3
Chongqing University of Arts and Sciences
Chongqing University of Arts and Sciences
Chongqing University of Arts and Sciences
LEAD_AUTHOR