Generalized numerical ranges of matrix polynomials
G.
Aghamollaei
Shahid Bahonar University of Kerman, Kerman, Iran
author
N.
Avizeh
Shahid Bahonar University of Kerman, Kerman, Iran
author
Y.
Jahanshahi
Shahid Bahonar University of Kerman, Kerman, Iran
author
text
article
2013
eng
In this paper, we introduce the notions of C-numerical range and C-spectrum of matrix polynomials. Some algebraic and geometrical properties are investigated. We also study the relationship between the C-numerical range of a matrix polynomial and the joint C-numerical range of its coefficients.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
789
803
http://bims.iranjournals.ir/article_443_674a1b7f8ad80f809ad9ae7135dde7f9.pdf
A new proof for the Banach-Zarecki theorem: A light
on integrability and continuity
A.
Mahdipour Shirayeh
Postdoctoral Researcher, Brock University, Canada
author
H.
Eshraghi
Assistant Professor, Iran University of Science and Technology
author
text
article
2013
eng
To demonstrate more visibly the close relation between thecontinuity and integrability, a new proof for the Banach-Zareckitheorem is presented on the basis of the Radon-Nikodym theoremwhich emphasizes on measure-type properties of the Lebesgueintegral. The Banach-Zarecki theorem says that a real-valuedfunction $F$ is absolutely continuous on a finite closed intervalif and only if it is continuous and of bounded variation when itsatisfies Lusin's condition. In the present proof indeed a moregeneral result is obtained for the Jordan decomposition of $F$.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
805
819
http://bims.iranjournals.ir/article_444_c68c238e1dfeb0e5bc9a083db174fee9.pdf
On a class of systems of n Neumann two-point boundary value Sturm-Liouville type equations
S.
Heidarkhani
Razi university of Kermanshah
author
text
article
2013
eng
Employing a three critical points theorem, we prove the existence ofmultiple solutions for a class of Neumann two-point boundary valueSturm-Liouville type equations. Using a local minimum theorem fordifferentiable functionals the existence of at least one non-trivialsolution is also ensured.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
821
840
http://bims.iranjournals.ir/article_445_696e71ccb7bc3450096d4b5d2c3603ef.pdf
Some combinatorial aspects of finite Hamiltonian groups
M.
Tarnauceanu
Faculty of Mathematics, "Al. I. Cuza" University
author
text
article
2013
eng
In this paper we provide explicit formulas for the number of elements/subgroups/cyclic subgroups of a given order and for the total number of subgroups/cyclic subgroups in a finite Hamiltonian group. The coverings with three proper subgroups and the principal series of such a group are also counted. Finally, we give a complete description of the lattice of characteristic subgroups of a finite Hamiltonian group.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
841
854
http://bims.iranjournals.ir/article_446_709d30bd2ac8176682140ee62d6a4254.pdf
Analytic solutions for the Stephen's inverse problem with local boundary conditions including Elliptic and hyperbolic equations
M.
Jahanshahi
Azarbaijan university of Tarbiat Moallem
author
M.
Sajjadmanesh
Azarbaijan university of Tarbiat Moallem
author
text
article
2013
eng
In this paper, two inverse problems of Stephen kind with local (Dirichlet) boundary conditions are investigated. In the first problem only a part of boundary is unknown and in the second problem, the whole of boundary is unknown. For the both of problems, at first, analytic expressions for unknown boundary are presented, then by using these analytic expressions for unknown boundaries and boundary conditions of main problem, analytic solution of unknown function of main inverse problem is calculated.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
855
864
http://bims.iranjournals.ir/article_447_4872092001e98d09eefc38bf2ce9a651.pdf
Linear preservers of g-row and g-column majorization on
M_{n,m}
A.
Armandnejad
Vali-e-Asr University of Rafsanjan
author
Z.
Mohammadi
Vali-e-Asr University of Rafsanjan
author
F.
Akbarzadeh
Vali-e-Asr University of Rafsanjan
author
text
article
2013
eng
Let A and B be n × m matrices. The matrix B is said to be g-row majorized (respectively g-column majorized) by A, if every row (respectively column) of B, is g-majorized by the corresponding row (respectively column) of A. In this paper all kinds of g-majorization are studied on Mn,m, and the possible structure of their linear preservers will be found. Also all linear operators T : Mn,m ---> Mn,m preserving (or strongly preserving) g-row or g-column majorization will be characterized.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
865
880
http://bims.iranjournals.ir/article_448_1a08baec65b24a4816d12f8601a75dd7.pdf
Tutte polynomials of wheels via generating functions
C.
Brennan
University of the Witwatersrand
author
T.
Mansour
University of Haifa
author
E.
Mphako-Banda
University of Witwatersrand
author
text
article
2013
eng
We find an explicit expression of the Tutte polynomial of an $n$-fan. We also find a formula of the Tutte polynomial of an $n$-wheel in terms of the Tutte polynomial of $n$-fans. Finally, we give an alternative expression of the Tutte polynomial of an $n$-wheel and then prove the explicit formula for the Tutte polynomial of an $n$-wheel.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
881
891
http://bims.iranjournals.ir/article_449_8f1dce2d9821f65d9680e61e1825f866.pdf
A degree bound for the Graver basis of non-saturated lattices
H.
Sabzrou
Assistant Professor of University of Tehran
author
text
article
2013
eng
Let $L$ be a lattice in $ZZ^n$ of dimension $m$. We prove that there exist integer constants $D$ and $M$ which are basis-independent such that the total degree of any Graver element of $L$ is not greater than $m(n-m+1)MD$. The case $M=1$ occurs precisely when $L$ is saturated, and in this case the bound is a reformulation of a well-known bound given by several authors. As a corollary, we show that the Castelnuovo-Mumford regularity of the corresponding lattice ideal $I_L$ is not greater than $rac{1}{2}m(n-1)(n-m+1)MD$.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
893
901
http://bims.iranjournals.ir/article_450_c921d0b4177605ebd0c5e86cc49f45eb.pdf
Applications of Epi-Retractable and Co-Epi-Retractable Modules
H.
Mostafanasab
Isfahan university of Technology
author
text
article
2013
eng
A module M is called epi-retractable if every submodule of M is a homomorphic image of M. Dually, a module M is called co-epi-retractable if it contains a copy of each of its factor modules. In special case, a ring R is called co-pli (resp. co-pri) if RR (resp. RR) is co-epi-retractable. It is proved that if R is a left principal right duo ring, then every left ideal of R is an epi-retractable R-module. A co-pli strongly prime ring R is a simple ring. A left self-injective co-pli ring R is left Noetherian if and only if R is a left perfect ring. It is shown that a cogenerator ring R is a pli ring if and only if it is a co-pri ring. Moreover, if R is a left perfect ring such that every projective R-module is co-epi-retractable, then R is a quasi-Frobenius ring.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
903
917
http://bims.iranjournals.ir/article_451_a85b04c9d7350c032000bab9ef5951af.pdf
On Generalization of prime submodules
M.
Ebrahimpour
Shahid Bahonar University Of Kerman
author
R.
Nekooei
Shahid Bahonar University of Kerman
author
text
article
2013
eng
Let R be a commutative ring with identity and M be a unitary R-module. Let : S(M) −! S(M) [ {;} be a function, where S(M) is the set of submodules ofM. Suppose n 2 is a positive integer. A proper submodule P of M is called(n − 1, n) − -prime, if whenever a1, . . . , an−1 2 R and x 2 M and a1 . . . an−1x 2P(P), then there exists i 2 {1, . . . , n − 1} such that a1 . . . ai−1ai+1 . . . an−1x 2 Por a1 . . . an−1 2 (P : M). In this paper we study (n − 1, n) − -prime submodules(n 2). A number of results concerning (n−1, n)−-prime submodules are given.Modules with the property that for some , every proper submodule is (n−1, n)−-prime, are characterized and we show that under some assumptions (n−1, n)-primesubmodules and (n − 1, n) − m-prime submodules coincide (n,m 2).
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
919
939
http://bims.iranjournals.ir/article_452_42eb5d8e97c6430058365474fa12dd8f.pdf
POS-groups with some cyclic Sylow
subgroups
R.
Shen
Department of Mathematics, Hubei University for Nationalities,
Enshi, Hubei Province, 445000, P. R. China
author
W. J.
Shi
author
J.
Shi
LMAM & School of Mathematical Sciences, Peking University,
Beijing, 100871, P. R. China
author
text
article
2013
eng
A finite group G is said to be a POS-group if for each x in G the cardinality of the set {y in G | o(y) = o(x)} is a divisor of the order of G. In this paper we study the structure of POS-groups with some cyclic Sylow subgroups.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
941
957
http://bims.iranjournals.ir/article_453_d4b01d3e0d15bc7e4701de7239c02219.pdf
Biflatness of certain semigroup algebras
M.
Essmaili
Kharazmi university (Tarbiat Moallem )
author
A.
Medghalchi
Kharazmi University (Tarbiat Moallem)
author
text
article
2013
eng
In the present paper, we consider biflatness of certain classes of semigroupalgebras. Indeed, we give a necessary condition for a band semigroup algebra to bebiflat and show that this condition is not sufficient. Also, for a certain class of inversesemigroups S, we show that the biflatness of ell^{1}(S)^{primeprime} is equivalent to the biprojectivity of ell^{1}(S).
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
959
969
http://bims.iranjournals.ir/article_454_f4fa201bf0a879cd7aca81e3b061050e.pdf
G-positive and G-repositive solutions to some adjointable operator equations over Hilbert C^{∗}-modules
G.
Song
University of Weifang, P. R. China
author
text
article
2013
eng
Some necessary and sufficient conditions are given for the existence of a G-positive (G-repositive) solution to adjointable operator equations $AX=C,AXA^{left( astright) }=C$ and $AXB=C$ over Hilbert $C^{ast}$-modules, respectively. Moreover, the expressions of these general G-positive (G-repositive) solutions are also derived. Some of the findings of this paper extend some known results in the literature.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
971
992
http://bims.iranjournals.ir/article_455_cdee254edff96f8755573457f8b11ff8.pdf
Geodesic metric spaces and generalized nonexpansive multivalued mappings
A.
Abkar
Imam Khomeini International University
author
M.
Eslamian
Imam Khomeini International University
author
text
article
2013
eng
In this paper, we present some common fixed point theorems for two generalized nonexpansive multivalued mappings in CAT(0) spaces as well as in UCED Banach spaces. Moreover, we prove the existence of fixed points for generalized nonexpansive multivalued mappings in complete geodesic metric spaces with convex metric for which the asymptotic center of a bounded sequence in a bounded closed convex subset is nonempty and singleton. The results obtained in this paper extend and improve some recent results.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
993
1008
http://bims.iranjournals.ir/article_456_9a60fdb5fa9a311ab14cfc56137c9f3b.pdf
Ricci tensor for $GCR$-lightlike submanifolds of indefinite Kaehler manifolds
R.
Nagaich
Department of Mathematics, Punjabi University,
Patiala 147 002. India
author
R.
Kumar
University College of Engineering
Punjabi University, Patiala, India
author
S.
Kumar
Department of Applied Sciences, Chitkara University, India
author
text
article
2013
eng
We obtain the expression of Ricci tensor for a $GCR$-lightlikesubmanifold of indefinite complex space form and discuss itsproperties on a totally geodesic $GCR$-lightlike submanifold of anindefinite complex space form. Moreover, we have proved that everyproper totally umbilical $GCR$-lightlike submanifold of anindefinite Kaehler manifold is a totally geodesic $GCR$-lightlikesubmanifold.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
1009
1029
http://bims.iranjournals.ir/article_457_30835d587e52fae1944d0dcc1ecbd3ab.pdf
Limit distribution of the degrees in scaled attachment random recursive trees
M.
Javanian
Department of Statistics, Zanjan University, Zanjan, Iran
author
text
article
2013
eng
We study the limiting distribution of the degree of a given node in a scaled attachment random recursive tree, a generalized random recursive tree, which is introduced by Devroye et. al (2011). In a scaled attachment random recursive tree, every node $i$ is attached to the node labeled $lfloor iX_i floor$ where $X_0$, $ldots$ , $X_n$ is a sequence of i.i.d. random variables, with support in [0, 1) and distribution function $F$. By imposing a condition on $F$, we show that the degree of a given node is asymptotically normal.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
1031
1036
http://bims.iranjournals.ir/article_458_63e25d39e913e72ed5c4039ad4b7b99d.pdf
On the Fischer-Clifford matrices of a maximal subgroup of the Lyons group Ly
J.
Moori
University of North-West, Mafikeng, South Africa
author
T.
Seretlo
University of North-West, Mafikeng, South Africa
author
text
article
2013
eng
The non-split extension group $overline{G} = 5^3{^.}L(3,5)$ is a subgroup of order 46500000 and of index 1113229656 in Ly. The group $overline{G}$ in turn has L(3,5) and $5^2{:}2.A_5$ as inertia factors. The group $5^2{:}2.A_5$ is of order 3 000 and is of index 124 in L(3,5). The aim of this paper is to compute the Fischer-Clifford matrices of $overline{G}$, which together with associated partial character tables of the inertia factor groups, are used to compute a full character table of $overline{G}$. A partial projective character table corresponding to $5^2{:}2A_5$ is required, hence we have to compute the Schur multiplier and projective character table of $5^2{:}2A_5$.
Bulletin of the Iranian Mathematical Society
Iranian Mathematical Society (IMS)
1017-060X
39
v.
5
no.
2013
1037
1052
http://bims.iranjournals.ir/article_459_58273f9efd05d9a6da2fc3790b5110c6.pdf