2019-01-20T16:39:18Z
http://jas.shahroodut.ac.ir/?_action=export&rf=summon&issue=101
Journal of Algebraic Systems
JAS
2345-5128
2345-5128
2016
4
1
ON RELATIVE CENTRAL EXTENSIONS AND COVERING PAIRS
A.
Pourmirzaei
M.
Hassanzadeh
B.
Mashayekhy
Let (G;N) be a pair of groups. In this article, first we con-struct a relative central extension for the pair (G;N) such that specialtypes of covering pair of (G;N) are homomorphic image of it. Second, weshow that every perfect pair admits at least one covering pair. Finally,among extending some properties of perfect groups to perfect pairs, wecharacterize covering pairs of a perfect pair (G;N) under some extraassumptions.
Pair of groups
Covering pair
Relative central extension
Isoclinism of pairs of groups
2016
09
01
1
13
http://jas.shahroodut.ac.ir/article_724_70e8def60b0539607f4789672c9b8d32.pdf
Journal of Algebraic Systems
JAS
2345-5128
2345-5128
2016
4
1
SOME REMARKS ON GENERALIZATIONS OF MULTIPLICATIVELY CLOSED SUBSETS
M.
Ebrahimpour
Let R be a commutative ring with identity and Mbe a unitary R-module. In this paper we generalize the conceptmultiplicatively closed subset of R and we study some propertiesof these genaralized subsets of M. Among the many results in thispaper, we generalize some well-known theorems about multiplicativelyclosed subsets of R to these generalized subsets of M. Alsowe show that some other well-known results about multiplicativelyclosed subsets of R are not valid for these generalized subsets ofM.
Multiplication module
Multiplicatively closed subset of R
(n
2016
09
01
15
27
http://jas.shahroodut.ac.ir/article_725_cb149f0b8733858d64345565c0ffefb6.pdf
Journal of Algebraic Systems
JAS
2345-5128
2345-5128
2016
4
1
ON FINITE GROUPS IN WHICH SS-SEMIPERMUTABILITY IS A TRANSITIVE RELATION
S.E.
Mirdamadi
Gh.R
Rezaeezadeh
Let H be a subgroup of a finite group G. We say that H is SS-semipermutable in Gif H has a supplement K in G such that H permutes with every Sylow subgroup X of Kwith (jXj; jHj) = 1. In this paper, the Structure of SS-semipermutable subgroups, and finitegroups in which SS-semipermutability is a transitive relation are described. It is shown thata finite solvable group G is a PST-group if and only if whenever H K are two p-subgroupsof G, H is SS-semipermutable in NG(K).
SS-semipermutable subgroups
S-semipermutable subgroups
PST-groups
2016
09
01
29
36
http://jas.shahroodut.ac.ir/article_726_4dada44a60bbc33404cb7f7dcf783e40.pdf
Journal of Algebraic Systems
JAS
2345-5128
2345-5128
2016
4
1
ON COMPOSITION FACTORS OF A GROUP WITH THE SAME PRIME GRAPH AS Ln(5)
A.
Mahmoudifar
The prime graph of a finite group $G$ is denoted by$ga(G)$. A nonabelian simple group $G$ is called quasirecognizable by primegraph, if for every finite group $H$, where $ga(H)=ga(G)$, thereexists a nonabelian composition factor of $H$ which is isomorphic to$G$. Until now, it is proved that some finite linear simple groups arequasirecognizable by prime graph, for instance, the linear groups $L_n(2)$ and $L_n(3)$ are quasirecognizable by prime graph. In this paper, we consider thequasirecognition by prime graph of the simple group $L_n(5)$.
projective special linear group
prime graph
element order
2016
09
01
37
51
http://jas.shahroodut.ac.ir/article_727_c70536bdd3b43cb9e978c4423102d125.pdf
Journal of Algebraic Systems
JAS
2345-5128
2345-5128
2016
4
1
STRONGLY DUO AND CO-MULTIPLICATION MODULES
S.
Safaeeyan
Let R be a commutative ring. An R-module M is called co-multiplication provided that foreach submodule N of M there exists an ideal I of R such that N = (0 : I). In this paper weshow that co-multiplication modules are a generalization of strongly duo modules. Uniserialmodules of finite length and hence valuation Artinian rings are some distinguished classes ofco-multiplication rings. In addition, if R is a Noetherian ring, then R is a strongly duoring if and only if R is a co-multiplication ring. We also show that J-semisimple strongly duorings are precisely semisimple rings. Moreover, if R is a perfect ring, then uniserial R-modules are co-multiplication of finite length modules. Finally, we showthat Abelian co-multiplication groups are reduced and co-multiplication Z-modules(Abeliangroups)are characterized.
Co-multiplication modules
strongly duo modules
Abelian Groups
2016
09
01
53
64
http://jas.shahroodut.ac.ir/article_728_14be7a662ba6a73829b723a3c29433f9.pdf
Journal of Algebraic Systems
JAS
2345-5128
2345-5128
2016
4
1
SIGNED ROMAN DOMINATION NUMBER AND JOIN OF GRAPHS
A.
Behtoei
E.
Vatandoost
F.
Azizi Rajol Abad
In this paper we study the signed Roman dominationnumber of the join of graphs. Specially, we determine it for thejoin of cycles, wheels, fans and friendship graphs.
Signed Roman domination
Join
Cycle
Wheel
Friendship
2016
09
01
65
77
http://jas.shahroodut.ac.ir/article_729_e681cf062e236a6c154451d27072c3cb.pdf
Journal of Algebraic Systems
JAS
2345-5128
2345-5128
2016
4
1
ARTINIANNESS OF COMPOSED LOCAL COHOMOLOGY MODULES
H.
Saremi
Let $R$ be a commutative Noetherian ring and let $fa$, $fb$ be two ideals of $R$ such that $R/({fa+fb})$ is Artinian. Let $M$, $N$ be two finitely generated $R$-modules. We prove that $H_{fb}^j(H_{fa}^t(M,N))$ is Artinian for $j=0,1$, where $t=inf{iin{mathbb{N}_0}: H_{fa}^i(M,N)$ is not finitelygenerated $}$. Also, we prove that if $DimSupp(H_{fa}^i(M,N))leq 2$, then $H_{fb}^1(H_{fa}^i(M,N))$ is Artinian for all $i$. Moreover, we show that if $dim N=d$, then $H_{fb}^j(H_{fa}^{d-1}(N))$ is Artinian for all $jgeq 1$.
Generalized local cohomology
Local cohomology
Artinian modules
2016
09
01
79
84
http://jas.shahroodut.ac.ir/article_730_b73d8831c14ac1772432c3f6a0548594.pdf