2018-10-22T16:48:36Z
http://bims.iranjournals.ir/?_action=export&rf=summon&issue=57
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
On the spectra of some matrices derived from two quadratic matrices
H.
Ozdemir
T.
Petik
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}
Quadratic matrix
idempotent matrix
spectrum
linear combination
diagonalization
2013
05
01
225
238
http://bims.iranjournals.ir/article_337_6b4319d54520d67fc847630c7c2cac10.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
The least-square bisymmetric solution to a quaternion matrix equation with applications
Q.
Wang
G.
Yu
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.
Quaternion matrix equation
bisymmetric matrix
least-square solution
Inertia
2013
05
15
239
257
http://bims.iranjournals.ir/article_340_5bfe11787a82c95ca80797926f05c97f.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
Optimal convex combinations bounds of centrodial and harmonic means for logarithmic and identric means
Y.
Chu
S.
Hou
W.
Xia
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)
logarithmic mean
identric mean
centroidal mean
harmonic mean
2013
05
15
259
269
http://bims.iranjournals.ir/article_411_ce7ebf9563324f84f8dface04487e196.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
Finite groups with three relative commutativity degrees
R.
Barzegar
A.
Erfanian
M.
Farrokhi D. G.
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.
Commutativity degree
relative commutativity degree
isoclinism
relative isoclinism
2013
05
15
271
280
http://bims.iranjournals.ir/article_412_c7a8a12e199ac1ff4482cfd330bf4466.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
Gorenstein flat and Gorenstein injective dimensions of simple modules
A.
Xu
X.
Yan
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.
Gorenstein flat dimension
Gorenstein injective dimension
simple module
2013
05
15
281
287
http://bims.iranjournals.ir/article_413_0c2096907897563917352df573b7123b.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
Quasirecognition by the prime graph of L_3(q) where 3 < q < 100
S. S.
Salehi Amiri
A.
Khalili Asboei
A.
Iranmanesh
A.
Tehranian
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.
Prime graph
element order
simple group
linear group
2013
05
01
289
305
http://bims.iranjournals.ir/article_414_abb286fd32fe231f0647dce9cdb1cae2.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
Existence of positive solutions for a boundary value problem of a nonlinear fractional differential equation
F.
Torres
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.
Caputo derivative
cone
fixed point theorem
Fractional differential equation
positive solutions
2013
05
15
307
323
http://bims.iranjournals.ir/article_415_bcc9076ae61d66e52701f70a718d0c42.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
On H-cofinitely supplemented modules
Y.
Talebi
R.
Tribak
A.
Moniri Hamzekolaei
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
H-supplemented module
H-cofinitely supplemented module
radical-projective module
2013
05
15
325
346
http://bims.iranjournals.ir/article_416_a39509657a78fc90c5d27db44e1ed1d3.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
Hyers-Ulam-Rassias stability of n-Jordan *-homomorphisms on C*-algebras
Sh.
Ghaffary Ghaleh
Kh.
Ghasemi
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.
Hyers-Ulam-Rassias stability
n-Jordan *-homomorphism
n-jordan homomorphism
C*-algebra
2013
05
15
347
353
http://bims.iranjournals.ir/article_417_c380aae386a841b43bbf3cd5bd085049.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
Ore extensions of skew $pi$-Armendariz rings
O.
Lunqun
L.
Jingwang
X.
Yueming
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.
skew Armendariz ring
skew $pi$-Armendariz ring
$pi$-Armendariz ring
2013
05
15
355
368
http://bims.iranjournals.ir/article_315_670f68e3782d06daa57d42c7aaf944da.pdf
Bulletin of the Iranian Mathematical Society
BIMS
1017-060X
1017-060X
2013
39
2
On the fixed point theorems in generalized weakly contractive mappings on partial metric spaces
K.
Chi
E.
Karapinar
T.
Thanh
In this paper, we prove a fixed 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.
fixed point theorems
partial metric spaces
weakly contractive mappings
2013
05
01
369
381
http://bims.iranjournals.ir/article_344_9cee21f500eec7a4df3245b5b9a8734e.pdf