eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-10-01
3
2
97
107
10.22044/jas.2015.610
610
AMENABILITY OF VECTOR VALUED GROUP ALGEBRAS
Ali Ghaffari
aghaffari@semnan.ac.ir
1
Seyedeh Samaneh Javadi Syahkale
s.javadi62@gmail.com
2
Department of Mathematics, Semnan University, Semnan, Iran
Faculty of Engineering- East Guilan, University of Guilan, Rudsar, Iran
The purpose of this article is to develop the notions of amenability<br />for vector valued group algebras. We prove that L1(G, A) is approximately<br />weakly amenable where A is a unital separable Banach algebra. We give<br />necessary and sufficient conditions for the existence of a left invariant mean<br />on L∞(G, A∗), LUC(G, A∗), WAP(G, A∗) and C0(G, A∗).
http://jas.shahroodut.ac.ir/article_610_80140794b33ad022f3303e700e885240.pdf
Amenability
banach algebras
derivation
group algebra
invariant mean
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
109
125
10.22044/jas.2015.611
611
IDEALS IN EL-SEMIHYPERGROUPS ASSOCIATED TO ORDERED SEMIGROUPS
S. H. Ghazavi
s.h.ghazavi@ashrafi.ac.ir
1
S. M. Anvariyeh
anvariyeh@yazd.ac.ir
2
S. Mirvakili
saeed_mirvakili@pnu.ac.ir
3
Department of Mathematics-Yazd University-Yazd-Iran
Department Of Mathematics-Yazd University-Yazd-Iran
Department of Mathematics, Payame Noor University, Tehran, Iran
In this paper, we attempt to investigate the connection between various types of ideals (for examples $(m, n)$-ideal, bi-ideal, interior ideal, quasi ideal, prime ideal and maximal ideal)<br /> of an ordered semigroup $(S,cdot ,leq)$ and the correspond hyperideals of its EL-hyperstructure $(S,*)$ (if exists). Moreover, we construct the class of EL-$Gamma$-semihypergroup associated to a partially ordered $Gamma$-semigroup.
http://jas.shahroodut.ac.ir/article_611_edab4a829eab96599e8b252cfea28168.pdf
(M
n)-ideal
interior ideal
Ends lemma
EL-hyperstructures
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
127
131
10.22044/jas.2015.612
612
ON ABSOLUTE CENTRAL AUTOMORPHISMS FIXING THE CENTER ELEMENTWISE
Z. Kaboutari Farimani
kaboutarizf@gmail.com
1
M. M. Nasrabadi
mnasrabadi@birjand.ac.ir
2
Department of Mathematics, University of Birjand, Birjand, Iran.
Department of Mathematics, University of Birjand, Birjand, Iran.
Let G be a finite p-group and let Aut_l(G) be the group of absolute central automorphisms of G. In this paper we give necessary and sufficient condition on G such that each absolute central automorphism of G fixes the centre element-wise. Also we classify all groups of orders p^3 and p^4 whose absolute central automorphisms fix the centre element-wise.
http://jas.shahroodut.ac.ir/article_612_1811e3d5e5fb09d4b5f4e6ce4fb36612.pdf
Absolute centre
absolute central automorphisms
finite p-groups
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
133
146
10.22044/jas.2015.613
613
ON GRADED LOCAL COHOMOLOGY MODULES DEFINED BY A PAIR OF IDEALS
M. Jahangiri
jahangiri@khu.ac.ir
1
Z. Habibi
z_habibi@pnu.ac.ir
2
Faculty of Mathematical Sciences and Computer, Kharazmi University, Tehran, Iran AND Institute for Research in Fundamental Sciences (IPM) P.O.Box: 19395- 5746, Tehran, Iran.
Department of Mathematics, University of Payame Noor, P.O.Box 19395-3697, Tehran, Iran.
Let $R = bigoplus_{n in mathbb{N}_{0}} R_{n}$ be a standard<br />graded ring, $M$ be a finitely generated graded $R$-module and $J$<br />be a homogenous ideal of $R$. In this paper we study the graded<br />structure of the $i$-th local cohomology module of $M$ defined by a<br />pair of ideals $(R_{+},J)$, i.e. $H^{i}_{R_{+},J}(M)$. More<br />precisely, we discuss finiteness property and vanishing of the<br />graded components $H^{i}_{R_{+},J}(M)_{n}$.<br /><br />Also, we study the Artinian property and tameness of certain<br />submodules and quotient modules of $H^{i}_{R_{+},J}(M)$.
http://jas.shahroodut.ac.ir/article_613_c40acc726617eb0a6a9ca9a12b7a2e55.pdf
graded modules
local cohomology module with respect to a
pair of ideals
Artinian modules
tameness
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
147
150
10.22044/jas.2015.614
614
RESULTS ON ALMOST COHEN-MACAULAY MODULES
A. Mafi
a_mafi@ipm.ir
1
S. Tabejamaat
samanetabejamaat_golestan@yahoo.com
2
Department of Mathematics, University of Kurdistan, P.O.Box 416, Sanandaj, Iran.
Department of Mathematics, Payame Noor University, P.O.Box 19395-3697, Tehran, Iran.
Let $(R,underline{m})$ be a commutative Noetherian local ring and $M$ be a non-zero finitely generated $R$-module. We show that if $R$ is almost Cohen-Macaulay and $M$ is perfect with finite projective dimension, then $M$ is an almost Cohen-Macaulay module. Also, we give some necessary and sufficient condition on $M$ to be an almost Cohen-Macaulay module, by using $Ext$ functors.
http://jas.shahroodut.ac.ir/article_614_d7afaf2c070483f534a968021ba416ea.pdf
Almost Cohen-Macaulay modules
Cohen-Macaulay modules
Ext functors
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
151
169
10.22044/jas.2015.615
615
RATIONAL CHARACTER TABLE OF SOME FINITE GROUPS
H. Shabani
ghorbani30@gmail.com
1
A. R. Ashrafi
ashrafi@kashanu.ac.ir
2
M. Ghorbani
mghorbani@sru.ac.ir
3
Department of Pure Mathematics, Faculty of Mathematical Sciences, University of Kashan, Kashan 87317−51167, I. R. Iran.
Department of Pure Mathematics, Faculty of Mathematical Sciences, University of Kashan, Kashan 87317−51167, I. R. Iran.
Department of Mathematics, Faculty of Science, Shahid Rajaee Teacher Training University, Tehran, 16785 - 136, I. R. Iran.
The aim of this paper is to compute the rational character tables of the dicyclic group $T_{4n}$, the groups of order $pq$ and $pqr$. Some general properties of rational character tables are also considered into account.<br />The aim of this paper is to compute the rational character tables of the dicyclic group $T_{4n}$, the groups of order $pq$ and $pqr$. Some general properties of rational character tables are also considered into account.
http://jas.shahroodut.ac.ir/article_615_def3b04d2ccfdc9937fb673747390703.pdf
Rational character table
character table
Galois group
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
171
199
10.22044/jas.2015.616
616
MAGMA-JOINED-MAGMAS: A CLASS OF NEW ALGEBRAIC STRUCTURES
M. H. Hooshmand
hadi.hooshmand@gmail.com
1
Young Researchers and Elite Club, Shiraz Branch, Islamic Azad University, Shiraz, Iran.
By left magma-$e$-magma, I mean a set containing<br />the fixed element $e$, and equipped by two binary operations "$cdot$"<br />, $odot$ with the property $eodot (xcdot y)=eodot(xodot y)$, namely<br />left $e$-join law. So, $(X,cdot,e,odot)$ is a left magma-$e$-magma<br />if and only if $(X,cdot)$, $(X,odot)$ are magmas (groupoids), $ein X$ and the left $e$-join law holds.<br />Right (and two-sided) magma-$e$-magmas are defined in an analogous way.<br />Also, $X$ is magma-joined-magma if it is magma-$x$-magma, for all $xin X$. Therefore, we introduce a big class of basic<br />algebraic structures with two binary operations which some of their<br />sub-classes are group-$e$-semigroups, loop-$e$-semigroups, semigroup-$e$-quasigroups,<br />etc. A nice infinite [resp. finite] example for them is real group-grouplike $(mathbb{R},+,0,+_1)$ [resp. Klein group-grouplike].<br />In this paper, I introduce and study the topic, construct several big classes of such algebraic structures and characterize<br />all identical magma-$e$-magma in several ways. The motivation of this study lies in some<br /> interesting connections to $f$-Multiplications, some basic functional equations<br /> on algebraic structures and Grouplikes (recently been introduced by the author). At last, we show some of future directions<br />for the researches.
http://jas.shahroodut.ac.ir/article_616_129e9f74cb580b363d2f9eb90a41a37f.pdf
08A99
20N02
20M99
20N05
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
201
210
10.22044/jas.2015.618
618
NONNIL-NOETHERIAN MODULES OVER COMMUTATIVE RINGS
A. Yousefian Darani
youseffian@gmail.com
1
Department of Mathematics and Applications, University of Mohaghegh Ardabili, P.O.Box 5619911367, Ardabil, Iran.
In this paper we introduce a new class of modules which is closely related to the class of Noetherian modules. Let $R$ be a commutative ring with identity and let $M$ be an $R$-module such that $Nil(M)$ is a divided prime submodule of $M$. $M$ is called a Nonnil-Noetherian $R$-module if every nonnil submodule of $M$ is finitely generated. We prove that many of the properties of Noetherian modules are also true for Nonnil-Noetherian modules.
http://jas.shahroodut.ac.ir/article_618_ab7aebe1bfa094cd9b11cca2200588f0.pdf
Noetherian rings
Noetherian modules, Finitely generated submodules, Divided submodules, Phi-modules
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
211
215
10.22044/jas.2015.619
619
A SHORT PROOF OF A RESULT OF NAGEL
N. Shirmohammadi
shirmohammadi@tabrizu.ac.ir
1
Department of Mathematics, University of Tabriz, P.O.Box 51666-16471, Tabriz, Iran.
Let $(R,fm)$ be a Gorenstein local ring and<br />$M,N$ be two finitely generated modules over $R$. Nagel proved that if $M$ and $N$ are in<br />the same even liaison class, then<br />one has $H^i_{fm}(M)cong H^i_{fm}(N)$ for all $iIn this paper, we provide a short proof to this result.
http://jas.shahroodut.ac.ir/article_619_3984f444570261f2e3b6227586b24b67.pdf
Linkage
Local cohomology
quasi-Gorenstein module
eng
Shahrood University of Technology
Journal of Algebraic Systems
2345-5128
2345-511X
2015-01-01
3
2
217
225
10.22044/jas.2015.620
620
ON THE VANISHING OF DERIVED LOCAL HOMOLOGY MODULES
M. Hatamkhani
m-hatamkhani@araku.ac.ir
1
Department of Mathematics, Faculty of Science, Arak University, Arak, 38156-8-8349, Iran.
Let $R$ be a commutative Noetherian ring, $fa$ an<br />ideal of $R$ and $mathcal{D}(R)$ denote the derived category of<br />$R$-modules. For any homologically bounded complex $X$, we conjecture that<br />$sup {bf L}Lambda^{fa}(X)leq$ mag$_RX$. We prove this<br />in several cases. This generalize the main result of Hatamkhani and Divaani-Aazar cite{HD} for complexes.
http://jas.shahroodut.ac.ir/article_620_374b709d91ba6ee24f3f79fde8febcf8.pdf
Local cohomology modules
local homology modules
magnitude
Noetherian dimension