eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
295
323
498
Finite iterative methods for solving systems of linear matrix equations over reflexive and anti-reflexive matrices
Mehdi Dehghan
dehghan@aut.ac.ir
1
Masoud Hajarian
mhajarian@aut.ac.ir
2
Prof.
Department of Mathematics
Faculty of Mathematical Sciences
Shahid Beheshti University, G.C.,
Evin, Tehran 19839
Iran
A matrix $Pintextmd{C}^{ntimes n}$ is called a generalized reflection matrix if $P^{H}=P$ and $P^{2}=I$. An $ntimes n$ complex matrix $A$ is said to be a reflexive (anti-reflexive) matrix with respect to the generalized reflection matrix $P$ if $A=PAP$ ($A=-PAP$). In this paper, we introduce two iterative methods for solving the pair of matrix equations $AXB=C$ and $DXE=F$ over reflexive and anti-reflexive matrices. The convergence of the iterative methods is also proposed. Finally, a numerical example is given to show the efficiency of the presented results.
http://bims.iranjournals.ir/article_498_e826f705a8bcdc93e8b4e86ef70af573.pdf
Matrix equation
Reflexive matrix
Anti-reflexive matrix
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
325
337
499
Bilateral composition operators on vector-valued Hardy spaces
Hamid Rezaei
rezaei@mail.yu.ac.ir
1
Yasouj University
Let $T$ be a bounded operator on the Banach space $X$ and $ph$ be an analytic self-map of the unit disk $Bbb{D}$. We investigate some operator theoretic properties of bilateral composition operator $C_{ph, T}: f ri T circ f circ ph$ on the vector-valued Hardy space $H^p(X)$ for $1 leq p leq +infty$. Compactness and weak compactness of $C_{ph, T}$ on $H^p(X)$ are characterized and when $p=2$, a concrete formula for its adjoint is given.
http://bims.iranjournals.ir/article_499_de6518007dfc715846c6f2e18e395a31.pdf
vector-valued Hardy space
composition operator
linear fractional map
weak compactness
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
339
355
500
Periodically correlated and multivariate symmetric stable processes related to periodic and cyclic flows
Afshin Parvardeh
a.parvardeh@sci.ui.ac.ir
1
Sareh Goliforushani
sareh.goli@gmail.com
2
Ahmad Reza Soltani
soltani@kuc01.kuniv.edu.kw
3
Academic Professor
Academic Professor
Academic Professor
In this work we introduce and study discrete time periodically correlated stable processes and multivariate stationary stable processes related to periodic and cyclic flows. Our study involves producing a spectral representation and a spectral identification for such processes. We show that the third component of a periodically correlated stable process has a component related to a periodic-cyclic flow.
http://bims.iranjournals.ir/article_500_37ead49e70ddc70e5d343101a2a9cebe.pdf
multivariate stationary stable processes
flows
periodic and cyclic flows
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
357
371
501
Improvements of two preconditioned AOR iterative methods for Z-matrices
Mohsen Hasani
hasani.mo@gmail.com
1
Davod Khojasteh Salkuyeh
salkuyeh@gmail.com
2
Islamic Azad University
University of Guilan
In this paper, we propose two preconditioned AOR iterative methods to solve systems of linear equations whose coefficient matrices are Z-matrix. These methods can be considered as improvements of two previously presented ones in the literature. Finally some numerical experiments are given to show the effectiveness of the proposed preconditioners.
http://bims.iranjournals.ir/article_501_8a1c873672368b347de367b050646428.pdf
System of linear equations
preconditioner
AOR iterative method
Z-matrix
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
373
386
502
Ostrowski type inequalities for functions whose derivatives are preinvex
Imdat Işcan
imdat.iscan@giresun.edu.tr
1
Giresun University
In this paper, making use of a new identity, we establish new inequalities of Ostrowski type for the class of preinvex functions and gave some midpoint type inequalities.
http://bims.iranjournals.ir/article_502_aa3a54cac93833e16043e4a243cffb1f.pdf
Ostrowski type inequalities
preinvex function
condition C
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
387
398
503
On the decomposable numerical range of operators
Yousef Zamani
zamani@sut.ac.ir
1
Sima Ahsani
s-ahsani@sut.ac.ir
2
Sahand University of Technology
Sahand University of Technology
Let $V$ be an $n$-dimensional complex inner product space. Suppose $H$ is a subgroup of the symmetric group of degree $m$, and $chi :Hrightarrow mathbb{C} $ is an irreducible character (not necessarily linear). Denote by $V_{chi}(H)$ the symmetry class of tensors associated with $H$ and $chi$. Let $K(T)in
(V_{chi}(H))$ be the operator induced by $Tin
text{End}(V)$. The decomposable numerical range $W_{chi}(T)$ of
$T$ is a subset of the classical numerical range $W(K(T))$ of $K(T)$ defined as:$$
W_{chi}(T)={(K(T)x^{ast }, x^{ast}):x^{ast } is a decomposable unit tensor}.$$
In this paper, we study the interplay between the geometric properties of $W_{chi}(T)$ and the algebraic properties of $T$. In fact, we extend some of the results of [C. K. Li and A. Zaharia, Decomposable numerical range on orthonormal decomposable tensors, Linear Algebra Appl. 308 (2000), no, 1-3, 139--152] and [C. K. Li and A. Zaharia, Induced operators on symmetry classes of tensors, Trans. Amer. Math. Soc. 354 (2002), no. 2, 807--836], to non-linear irreducible characters.
http://bims.iranjournals.ir/article_503_b7e2e3cc8e6d67d8124fdf498d842b65.pdf
symmetry class of tensors
decomposable
numerical range
induced operator
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
399
411
504
WZ factorization via Abay-Broyden-Spedicato algorithms
Effat Golpar-Raboky
g_raboky@yahoo.com
1
N. Mahdavi-Amiri
nezamm@sharif.edu
2
University of Qom
Sharif University of Technology
Classes of Abaffy-Broyden-Spedicato (ABS) methods have been introduced for solving linear systems of equations. The algorithms are powerful methods for developing matrix factorizations and many fundamental numerical linear algebra processes. Here, we show how to apply the ABS algorithms to devise algorithms to compute the WZ and ZW factorizations of a nonsingular matrix as well as the $W^TW$ and $Z^TZ$ factorizations of a symmetric positives definite matrix. We also describe the QZ and the QW factorizations, with Q orthogonal, and show how to appropriate the parameters of the ABS algorithms to compute these factorizations.
http://bims.iranjournals.ir/article_504_cc2f035a33cf3308b3f1d82d42cd6624.pdf
ABS algorithms
WZ factorization
ZW factorizatio
WTW factorization
ZTZ factorization
QZ factoriation
QW factorization
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
413
421
505
A graphical difference between the inverse and regular semigroups
Ayoub Gharibkhajeh
a_gharib@iau-tnb.ac.ir
1
Hossein Doostie
doostih@tmu.ac.ir
2
Islamic Azad university North-Tehran Branch
Science and Research, Islamic Azad University Tehran- Iran
In this paper we investigate the Green graphs for the regular and inverse semigroups by considering the Green classes of them. And by using the properties of these semigroups, we prove that all of the five Green graphs for the inverse semigroups are isomorphic complete graphs, while this doesn't hold for the regular semigroups. In other words, we prove that in a regular semigroup $S$ two Green graph $Gamma_{mathcal{L}}(S)$ and $Gamma_{mathcal{H}}(S)$ are isomorphic, however, the other three Green graphs are non-isomorphic to them.
http://bims.iranjournals.ir/article_505_8d4a7f029daec49b029448a7f5252b20.pdf
Regular and inverse semigroup
Green relations
Green graphs
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
423
431
506
Gorenstein global dimensions for Hopf algebra actions
Qunxing Pan
pqxjs98@njau.edu.cn
1
Faqun Cai
cfq1217@163.com
2
Department of Mathematics, Nanjing Agricultural University
Department of Economic Management, Nanjing College of Chemical Technology
Let $H$ be a Hopf algebra and $A$ an $H$-bimodule algebra. In this paper, we investigate Gorenstein global dimensions for Hopf algebras and twisted smash product algebras $Astar H$. Results from the literature are generalized.
http://bims.iranjournals.ir/article_506_9440f67571725993f34bcd0d32f3296c.pdf
Hopf algebras
Gorenstein global
dimensions
Morita equivalence
twisted smash products
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
433
445
507
$(m,n)$-algebraically compactness and $(m,n)$-pure injectivity
Mahmood Behboodi
mbehbood@cc.iut.ac.ir
1
Atefeh Ghorbani
a_ghorbani@cc.iut.ac.ir
2
Seyed Hossein Shojaee
hshojaee@math.iut.ac.ir
3
Isfahan University of Technology
Isfahan University of Technology
Isfahan university of technology
In this paper, we introduce the notion of $(m,n)$-algebraically compact modules as an analogue of algebraically compact modules and then we show that $(m,n)$-algebraically compactness and $(m,n)$-pure injectivity for modules coincide. Moreover, further characterizations of a $(m,n)$-pure injective module over a commutative ring are given.
http://bims.iranjournals.ir/article_507_09d25bec7f5a7b3bdf5caa983c9d38ba.pdf
(n
m)-pure exact
m)-pure injective
m)-algebraically compact
pure injective
algebraically compact
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
447
458
508
A Stochastic algorithm to solve multiple dimensional Fredholm integral equations of the second kind
Rahman Farnoosh
rfarnoosh@iust.ac.ir
1
Mahboubeh Aalaei
aalaei@iust.ac.ir
2
School of Mathematics, Iran University of Science and Technology.
School of Mathematics, Iran University of Science and Technology.
In the present work, a new stochastic algorithm is proposed to solve multiple dimensional Fredholm integral equations of the second kind. The solution of the integral equation is described by the Neumann series expansion. Each term of this expansion can be considered as an expectation which is approximated by a continuous Markov chain Monte Carlo method. An algorithm is proposed to simulate a continuous Markov chain with probability density function arisen from an importance sampling technique. Theoretical results are established in a normed space to justify the convergence of the proposed method. The method has a simple structure and it is a good candidate for parallelization because of the fact that many independent sample paths are used to estimate the solution. Numerical results are performed in order to confirm the efficiency and accuracy of the present work.
http://bims.iranjournals.ir/article_508_c94cabec98592f562c8a3e4567221f96.pdf
Fredholm integral equations
Monte Carlo method
Continuous Markov chain
Neumann series expansion
Importance sampling
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
459
472
509
On $I$-statistical and $I$-lacunary statistical convergence of order $alpha$
Pratulananda Das
pratulananda@yahoo.co.in
1
Ekrem Savas
ekremsavas@yahoo.com
2
Jadavpour University
Istanbul Commerce University
In this paper, following a very recent and new approach, we further generalize recently introduced summability methods, namely, $I$-statistical convergence and $I$-lacunary statistical convergence (which extend the important summability methods, statistical convergence and lacunary statistical convergence using ideals of $mathbb{N}$) and introduce the notions of $I$-statistical convergence of order $alpha$ and $I$-lacunary statistical convergence of order $alpha$, where $0
http://bims.iranjournals.ir/article_509_fe820582c3d031263737aa3b6e5a7007.pdf
I-statistical convergence
I-lacunary statistical convergence
statistical convergence of order $alpha$
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
473
480
510
A characterization of the symmetric group of prime degree
Qingliang Zhang
qingliangstudent@163.com
1
Jinhua Wang
jhwang@ntu.edu.cn
2
Weijun Liu
wjliu6210@126.com
3
School of Sciences, Nantong University, 226007, Nantong, P. R. China
School of Sciences, Nantong University, 226007, Nantong, P. R. China
School of Sciences, Nantong University, 226007, Nantong, P. R. China
Let $G$ be a finite group and $Gamma(G)$ the prime graph of $G$. Recently people have been using prime graphs to study simple groups. Naturally we pose a question: can we use prime graphs to study almost simple groups or non-simple groups? In this paper some results in this respect are obtained and as follows: $Gcong S_p$ if and only if $|G|=|S_p|$ and $Gamma(G)=Gamma(S_p)$, where $p$ is a prime.
http://bims.iranjournals.ir/article_510_dee5dd7e5a3f35385b5ddbc71bf0cc1b.pdf
characterization
symmetric group
Prime graph
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
481
504
511
Approximating fixed points of nonexpansive mappings and solving systems of variational inequalities
Hossein Piri
hossein_piri1979@yahoo.com
1
Department of Mathematics,
University of Bonab, Bonab 5551761167, Iran
A new approximation method for the set of common fixed points of nonexpansive mappings and the set of solutions of systems of variational inequalities is introduced and studied. Moreover, we apply our main result to obtain strong convergence theorem to a common fixed point of a nonexpannsive mapping and solutions of a system of variational inequalities of an inverse strongly monotone mapping and strictly pseudo-contractive mapping of Browder-Petryshyn type.
http://bims.iranjournals.ir/article_511_d0c5befcc72c8fd3470d89ccbd4d2ba3.pdf
fixed point
$delta$- strongly monotone
$lambda$- strictly pseudo-contractive
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
505
520
512
Arens regularity of bilinear forms and unital Banach module spaces
kazem Haghnejad Azar
haghnejadmath@yahoo.com
1
Faculty member of Mohghegh Ardabili Universsity
Assume that $A$, $B$ are Banach algebras and that $m:Atimes Brightarrow B$, $m^prime:Atimes Arightarrow B$ are bounded bilinear mappings. We study the relationships between Arens regularity of $m$, $m^prime$ and the Banach algebras $A$, $B$. For a Banach $A$-bimodule $B$, we show that $B$ factors with respect to $A$ if and only if $B^{**}$ is unital as an $A^{**}$-module. Let $Z_{e^{primeprime}}(B^{**})=B^{**}$ where $e^{primeprime}$ is a mixed unit of $A^{**}$. Then $B^*$ factors on both sides with respect to $A$ if and only if $B^{**}$ has a unit as $A^{**}$-module.
http://bims.iranjournals.ir/article_512_7cc3f3725b7b3c1fe554083605917069.pdf
Arens regularity
bilinear mappings
Topological center
Unital A-module
Module action
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
521
530
513
Weak Banach-Saks property in the space of compact operators
B. Khadijeh Moosavi
khmosavi@gmail.com
1
S. Mohammad Moshtaghioun
moshtagh90@gmail.com
2
Islamic Azad University, Bafgh Branch
Yazd University
For suitable Banach spaces $X$ and $Y$ with Schauder decompositions and a suitable closed subspace $mathcal{M}$ of some compact operator space from $X$ to $Y$, it is shown that the strong Banach-Saks-ness of all evaluation operators on ${mathcal M}$ is a sufficient condition for the weak Banach-Saks property of ${mathcal M}$, where for each $xin X$ and $y^*in Y^*$, the evaluation operators on $mathcal{M}$ are defined by $phi_x(T)= Tx$ and $psi_{y^*}(T)= T^*y^*.$
http://bims.iranjournals.ir/article_513_d1178361f94ff0d658d4159f2e3bc59b.pdf
weak Banach-Saks property
P- property
Schauder decomposition
compact operator
completely continuous operator
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2014-04-01
40
2
531
540
514
On generalisations of almost prime and weakly prime ideals
Mahdieh Ebrahimpour
mahdieh_ebrahimpour@yahoo.com
1
University of Vali-e-Asr
Let $R$ be a commutative ring with identity. A proper ideal $P$ of $R$ is a $(n-1,n)$-$Phi_m$-prime ($(n-1,n)$-weakly prime) ideal if $a_1,ldots,a_nin R$, $a_1cdots a_nin Pbackslash P^m$ ($a_1cdots a_nin Pbackslash {0}$) implies $a_1cdots a_{i-1}a_{i+1}cdots a_nin P$, for some $iin{1,ldots,n}$; ($m,ngeq 2$). In this paper several results concerning $(n-1,n)$-$Phi_m$-prime and $(n-1,n)$-weakly prime ideals are proved. We show that in a Noetherian domain a $Phi_m$-prime ideal is primary and we show that in some well known rings $(n-1,n)$-$Phi_m$-prime ideals and $(n-1,n)$-prime ideals coincide.
http://bims.iranjournals.ir/article_514_6d6ae9529874c4c6f84dc631664e5962.pdf
Quasi-local ring
prime ideal
almost prime ideal
$(n-1
n)$-weakly prime ideal
n)$-$Phi_m$-prime ideal