eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-01
39
5
789
803
443
Generalized numerical ranges of matrix polynomials
G. Aghamollaei
aghamollaei@uk.ac.ir
1
N. Avizeh
avizeh_narjes@yahoo.com
2
Y. Jahanshahi
yaser_j1986@yahoo.com
3
Shahid Bahonar University of Kerman, Kerman, Iran
Shahid Bahonar University of Kerman, Kerman, Iran
Shahid Bahonar University of Kerman, Kerman, Iran
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.
http://bims.iranjournals.ir/article_443_674a1b7f8ad80f809ad9ae7135dde7f9.pdf
matrix polynomial
C-numerical range
Joint C-numerical range
C-spectrum
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
805
819
444
A new proof for the Banach-Zarecki theorem: A light
on integrability and continuity
A. Mahdipour Shirayeh
ali.mahdipour@gmail.com
1
H. Eshraghi
eshraghi@iust.ac.ir
2
Postdoctoral Researcher, Brock University, Canada
Assistant Professor, Iran University of Science and Technology
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 $F$.
http://bims.iranjournals.ir/article_444_c68c238e1dfeb0e5bc9a083db174fee9.pdf
Banach-Zarecki theorem
Radon-Nikodym theorem
Lusin's condition
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
821
840
445
On a class of systems of n Neumann two-point boundary value Sturm-Liouville type equations
S. Heidarkhani
s.heidarkhani@razi.ac.ir
1
Razi university of Kermanshah
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.
http://bims.iranjournals.ir/article_445_696e71ccb7bc3450096d4b5d2c3603ef.pdf
Sturm-Liouville type System
Multiplicity results
Critical point theory
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
841
854
446
Some combinatorial aspects of finite Hamiltonian groups
M. Tarnauceanu
tarnauc@uaic.ro
1
Faculty of Mathematics, "Al. I. Cuza" University
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.
http://bims.iranjournals.ir/article_446_709d30bd2ac8176682140ee62d6a4254.pdf
Hamiltonian groups
Abelian groups
automorphisms
subgroups
subgroup coverings
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-01
39
5
855
864
447
Analytic solutions for the Stephen's inverse problem with local boundary conditions including Elliptic and hyperbolic equations
M. Jahanshahi
jahanshahi@azaruniv.edu
1
M. Sajjadmanesh
s.sajjadmanesh@azaruniv.edu
2
Azarbaijan university of Tarbiat Moallem
Azarbaijan university of Tarbiat Moallem
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.
http://bims.iranjournals.ir/article_447_4872092001e98d09eefc38bf2ce9a651.pdf
Local boundary conditions
Inverse problem
Fundamental solution
Dirac's delta function
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
865
880
448
Linear preservers of g-row and g-column majorization on
M_{n,m}
A. Armandnejad
armandnejad@gmail.com
1
Z. Mohammadi
z.mohammadi@stu.vru.ac.ir
2
F. Akbarzadeh
f.akbarzadeh@stu.vru.ac.ir
3
Vali-e-Asr University of Rafsanjan
Vali-e-Asr University of Rafsanjan
Vali-e-Asr University of Rafsanjan
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.
http://bims.iranjournals.ir/article_448_1a08baec65b24a4816d12f8601a75dd7.pdf
Linear preserver
g-row stochastic matrices
rgw-majorization
lgw-majorization
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
881
891
449
Tutte polynomials of wheels via generating functions
C. Brennan
charlotte.brennan@wits.ac.za
1
T. Mansour
toufik@math.haifa.ac.il
2
E. Mphako-Banda
eunice.mphako-banda@wits.ac.za
3
University of the Witwatersrand
University of Haifa
University of Witwatersrand
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.
http://bims.iranjournals.ir/article_449_8f1dce2d9821f65d9680e61e1825f866.pdf
Tutte polynomial
wheel
fan
generating function
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
893
901
450
A degree bound for the Graver basis of non-saturated lattices
H. Sabzrou
hossein@ipm.ir
1
Assistant Professor of University of Tehran
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 $rac{1}{2}m(n-1)(n-m+1)MD$.
http://bims.iranjournals.ir/article_450_c921d0b4177605ebd0c5e86cc49f45eb.pdf
Non-saturated lattices
Graver bases
lattice ideals
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
903
917
451
Applications of Epi-Retractable and Co-Epi-Retractable Modules
H. Mostafanasab
h.mostafanasab@gmail.com
1
Isfahan university of Technology
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.
http://bims.iranjournals.ir/article_451_a85b04c9d7350c032000bab9ef5951af.pdf
MSC(2010): Primary: 16D10, 16S50
Secondary: 16D40, 16E60
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
919
939
452
On Generalization of prime submodules
M. Ebrahimpour
mahdieh_ebrahimpour@yahoo.com
1
R. Nekooei
rnekooei@mail.uk.ac.ir
2
Shahid Bahonar University Of Kerman
Shahid Bahonar University of Kerman
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).
http://bims.iranjournals.ir/article_452_42eb5d8e97c6430058365474fa12dd8f.pdf
(n − 1, n) − prime submodule
Local ring
multiplication module
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-01
39
5
941
957
453
POS-groups with some cyclic Sylow
subgroups
R. Shen
shenrulin@hotmail.com
1
W. J. Shi
wjshi@suda.edu.cn
2
J. Shi
shi@suda.edu.cn
3
Department of Mathematics, Hubei University for Nationalities, Enshi, Hubei Province, 445000, P. R. China
LMAM & School of Mathematical Sciences, Peking University, Beijing, 100871, P. R. China
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.
http://bims.iranjournals.ir/article_453_d4b01d3e0d15bc7e4701de7239c02219.pdf
perfect order subset
POS-group
Frobenius group
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-01
39
5
959
969
454
Biflatness of certain semigroup algebras
M. Essmaili
m.essmaili@tmu.ac.ir
1
A. Medghalchi
medghal2000@yahoo.com
2
Kharazmi university (Tarbiat Moallem )
Kharazmi University (Tarbiat Moallem)
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).
http://bims.iranjournals.ir/article_454_f4fa201bf0a879cd7aca81e3b061050e.pdf
Biflatness
biprojectivity
semigroup algebras
inverse semigroup
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
971
992
455
G-positive and G-repositive solutions to some adjointable operator equations over Hilbert C^{∗}-modules
G. Song
sgjshu@yahoo.com.cn
1
University of Weifang, P. R. China
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.
http://bims.iranjournals.ir/article_455_cdee254edff96f8755573457f8b11ff8.pdf
Hilbert C^{∗}-module
generalized inverse
Operator equation
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
993
1008
456
Geodesic metric spaces and generalized nonexpansive multivalued mappings
A. Abkar
aliabkar99@gmail.com
1
M. Eslamian
mhmdeslamian@gmail.com
2
Imam Khomeini International University
Imam Khomeini International University
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.
http://bims.iranjournals.ir/article_456_9a60fdb5fa9a311ab14cfc56137c9f3b.pdf
fixed point
generalized nonexpansive mapping
CAT(0) space
geodesic metric space
asymptotic center
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
1009
1029
457
Ricci tensor for $GCR$-lightlike submanifolds of indefinite Kaehler manifolds
R. Nagaich
nagaichrakesh@yahoo.co.in
1
R. Kumar
dr_rk37c@yahoo.co.in
2
S. Kumar
sp7maths@gmail.com
3
Department of Mathematics, Punjabi University, Patiala 147 002. India
University College of Engineering Punjabi University, Patiala, India
Department of Applied Sciences, Chitkara University, India
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.
http://bims.iranjournals.ir/article_457_30835d587e52fae1944d0dcc1ecbd3ab.pdf
indefinite Kaehler Manifolds
GCR-lightlike submanifold
totally umbilical
lightlike submanifold
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-01
39
5
1031
1036
458
Limit distribution of the degrees in scaled attachment random recursive trees
M. Javanian
javanian_m@yahoo.com
1
Department of Statistics, Zanjan University, Zanjan, Iran
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.
http://bims.iranjournals.ir/article_458_63e25d39e913e72ed5c4039ad4b7b99d.pdf
trees
Recursive trees
Lyapunov's Theorem
eng
Iranian Mathematical Society (IMS)
Bulletin of the Iranian Mathematical Society
1017-060X
1735-8515
2013-10-15
39
5
1037
1052
459
On the Fischer-Clifford matrices of a maximal subgroup of the Lyons group Ly
J. Moori
jamshid.moori@nwu.ac.za
1
T. Seretlo
thekiso.seretlo@nwu.ac.za
2
University of North-West, Mafikeng, South Africa
University of North-West, Mafikeng, South Africa
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 $5^2{:}2A_5$.
http://bims.iranjournals.ir/article_459_58273f9efd05d9a6da2fc3790b5110c6.pdf
Group extensions
Lyons group
character table
Clifford theory Fischer-Clifford matrices