eng
Central Tehran Branch. IAU
Journal of Linear and Topological Algebra (JLTA)
2252-0201
2345-5934
2012-06-01
01
02
55
65
510112
Weak amenability of (2N)-th dual of a Banach algebra
M. Ettefagh
minaettefagh@gmail.com
1
S. Houdfar
2
Department of Mathematics, Tabriz Branch, Islamic Azad University, Tabriz, Iran
Department of Mathematics, Tabriz Branch, Islamic Azad University, Tabriz, Iran
In this paper by using some conditions, we show that the weak amenability of (2n)-th dual of a Banach algebra A for some $ngeq 1$ implies the weak amenability of A.
http://jlta.iauctb.ac.ir/article_510112_4481b97ff2be6b5aec88a2d5db69c502.pdf
Banach algebra
Arens porducts
Arens regularity
Derivation
weak amenability
eng
Central Tehran Branch. IAU
Journal of Linear and Topological Algebra (JLTA)
2252-0201
2345-5934
2012-06-01
01
02
67
69
510113
A note on uniquely (nil) clean ring
Sh. Sahebi
1
M. Jahandar
m66.jahandar@gmail.com
2
Department of Mathematics, Islamic Azad University, Central Tehran Branch, PO. Code 14168-94351, Iran
Department of Mathematics, Islamic Azad University, Central Tehran Branch, PO. Code 14168-94351, Iran
A ring R is uniquely (nil) clean in case for any $a in R$ there exists a uniquely idempotent $ein R$ such that $a-e$ is invertible (nilpotent). Let $C =(A V W B)$ be the Morita Context ring. We determine conditions under which the rings $A,B$ are uniquely (nil) clean. Moreover we show that the center of a uniquely (nil) clean ring is uniquely (nil) clean.
http://jlta.iauctb.ac.ir/article_510113_61313dd0e6f0354fd7ec465bb79fa807.pdf
Full element
uniquely clean ring
nil clean ring
eng
Central Tehran Branch. IAU
Journal of Linear and Topological Algebra (JLTA)
2252-0201
2345-5934
2012-06-01
01
02
71
81
510114
A mathematically simple method based on denition for computing eigenvalues, generalized eigenvalues and quadratic eigenvalues of matrices
M. Nili Ahmadabadi
nili@phu.iaun.ac.ir
1
Department of Mathematics, Islamic Azad University, Najafabad Branch, Iran
In this paper, a fundamentally new method, based on the denition, is introduced for numerical computation of eigenvalues, generalized eigenvalues and quadratic eigenvalues of matrices. Some examples are provided to show the accuracy and reliability of the proposed method. It is shown that the proposed method gives other sequences than that of existing methods but they still are convergent to the desired eigenvalues, generalized eigenvalues and quadratic eigenvalues of matrices. These examples show an interesting phenomenon in the procedure: The diagonal matrix that converges to eigenvalues gives them in decreasing order in the sense of absolute value. Appendices A to C provide Matlab codes that implement the proposed algorithms. They show that the proposed algorithms are very easy to program.
http://jlta.iauctb.ac.ir/article_510114_08524c96a88f2b589b9b2c9a46824457.pdf
Eigenvalue
Generalized eigenvalue
Quadratic eigenvalue
Numerical computation
Iterative method
eng
Central Tehran Branch. IAU
Journal of Linear and Topological Algebra (JLTA)
2252-0201
2345-5934
2012-06-01
01
02
83
95
510120
Numerical Solution of Heun Equation Via Linear Stochastic Differential Equation
H. R. Rezazadeh
h-rezazadeh@kiau.ac.ir
1
M. Maghasedi
maghasedi@kiau.ac.ir
2
B. shojaee
shoujaei@kiau.ac.ir
3
Department of Mathematics, Karaj Branch, Islamic Azad University, PO. Code 31485-313, Karaj, Iran
Department of Mathematics, Karaj Branch, Islamic Azad University, PO. Code 31485-313, Karaj, Iran
Department of Mathematics, Karaj Branch, Islamic Azad University, PO. Code 31485-313, Karaj, Iran
In this paper, we intend to solve special kind of ordinary differential equations which is called Heun equations, by converting to a corresponding stochastic differential equation(S.D.E.). So, we construct a stochastic linear equation system from this equation which its solution is based on computing fundamental matrix of this system and then, this S.D.E. is solved by numerically methods. Moreover, its asymptotic stability and statistical concepts like expectation and variance of solutions are discussed. Finally, the attained solutions of these S.D.E.s compared with exact solution of corresponding differential equations.
http://jlta.iauctb.ac.ir/article_510120_6b263c706914ad1317cfc87ee2468b82.pdf
Heun equation
Wiener process
Stochastic differential equation
Linear equations system
eng
Central Tehran Branch. IAU
Journal of Linear and Topological Algebra (JLTA)
2252-0201
2345-5934
2012-06-01
01
02
97
113
510116
A New Inexact Inverse Subspace Iteration for Generalized Eigenvalue Problems
M. Amirfakhrian
majiamir@yahoo.com
1
F. Mohammad
f.mohammad456@yahoo.com
2
Department of Mathematics, Islamic Azad University, Central Tehran Branch, PO. Code 14168-94351, Iran
Department of Mathematics, Islamic Azad University, Central Tehran Branch, PO. Code 14168-94351, Iran
In this paper, we represent an inexact inverse subspace iteration method for computing a few eigenpairs of the generalized eigenvalue problem Ax = Bx [Q. Ye and P. Zhang, Inexact inverse subspace iteration for generalized eigenvalue problems, Linear Algebra and its Application, 434 (2011) 1697-1715 ]. In particular, the linear convergence property of the inverse subspace iteration is preserved.
http://jlta.iauctb.ac.ir/article_510116_a6a495230d02a7daa80f2a110513ba3b.pdf
Eigenvalue problem
inexact inverse iteration
subspace iteration
inner-outer iteration
approximation
Convergence
eng
Central Tehran Branch. IAU
Journal of Linear and Topological Algebra (JLTA)
2252-0201
2345-5934
2012-06-01
01
02
111
114
510118
Module-Amenability on Module Extension Banach Algebras
D. Ebrahimi bagha
dav.ebrahimibagha@iauctb.ac.ir
1
Department of Mathematics, Faculty of Science, Islamic Azad University, Centeral Tehran Branch, P. O. Box 13185/768, Tehran, Iran
Let $A$ be a Banach algebra and $E$ be a Banach $A$-bimodule then $S = A oplus E$, the $l^1$-direct sum of $A$ and $E$ becomes a module extension Banach algebra when equipped with the algebras product $(a,x).(a^prime,x^prime)= (aa^prime, a.x^prime+ x.a^prime)$. In this paper, we investigate $triangle$-amenability for these Banach algebras and we show that for discrete inverse semigroup $S$ with the set of idempotents $E_S$, the module extension Banach algebra $S=l^1(E_S)oplus l^1(S)$ is $triangle$-amenable as a $l^1(E_S)$-module if and only if $l^1(E_S)$ is amenable as Banach algebra.
http://jlta.iauctb.ac.ir/article_510118_44c07398e7938ba779119a240cd4cf23.pdf
Module-amenability
module extension
Banach algebras
eng
Central Tehran Branch. IAU
Journal of Linear and Topological Algebra (JLTA)
2252-0201
2345-5934
2012-06-01
01
02
115
118
510119
E-Clean Matrices and Unit-Regular Matrices
Sh. A. Safari Sabet
1
S. Razaghi
2
Department of Mathematics, Islamic Azad University, Central Tehran Branch,Code 14168-94351, Iran
Department of Mathematics, Islamic Azad University, Central Tehran Branch,Code 14168-94351, Iran
Let $a, b, k,in K$ and $u, v in U(K)$. We show for any idempotent $ein K$, $(a 0|b 0)$ is e-clean iff $(a 0|u(vb + ka) 0)$ is e-clean and if $(a 0|b 0)$ is 0-clean, $(ua 0|u(vb + ka) 0)$ is too.
http://jlta.iauctb.ac.ir/article_510119_5c774e30071a0b38ec4b186ffdb5d653.pdf
Matrix ring
unimodular column
unit-regular
clean
e-clean
eng
Central Tehran Branch. IAU
Journal of Linear and Topological Algebra (JLTA)
2252-0201
2345-5934
2012-06-01
01
02
115
120
510117
Recognition of the group $G_2(5)$ by the prime graph
P. Nosratpour
p.nosratpour@ilam-iau.ac.ir
1
M. R. Darafsheh
2
Department of mathematics, ILam Branch, Islamic Azad university, Ilam, Iran
School of Mathematics, statistics and Computer Science, College of Science, University of Tehran, Tehran, Iran
Let $G$ be a finite group. The prime graph of $G$ is a graph $Gamma(G)$ with vertex set $pi(G)$, the set of all prime divisors of $|G|$, and two distinct vertices $p$ and $q$ are adjacent by an edge if $G$ has an element of order $pq$. In this paper we prove that if $Gamma(G)=Gamma(G_2(5))$, then $G$ has a normal subgroup $N$ such that $pi(N)subseteq{2,3,5}$ and $G/Nequiv G_2(5)$.
http://jlta.iauctb.ac.ir/article_510117_39d0770b34588d7c09328c4a5e5401be.pdf
prime graph
recognition
linear group