##### 1. ON RELATIVE CENTRAL EXTENSIONS AND COVERING PAIRS

A. Pourmirzaei; M. Hassanzadeh; B. Mashayekhy

Volume 4, Issue 1 , Summer and Autumn 2016, Pages 1-13

##### Abstract
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 ...  Read More

##### 2. SOME REMARKS ON GENERALIZATIONS OF MULTIPLICATIVELY CLOSED SUBSETS

M. Ebrahimpour

Volume 4, Issue 1 , Summer and Autumn 2016, Pages 15-27

##### Abstract
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 ...  Read More

##### 3. ON FINITE GROUPS IN WHICH SS-SEMIPERMUTABILITY IS A TRANSITIVE RELATION

Volume 4, Issue 1 , Summer and Autumn 2016, Pages 29-36

##### Abstract
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 ...  Read More

##### 4. ON COMPOSITION FACTORS OF A GROUP WITH THE SAME PRIME GRAPH AS Ln(5)

A. Mahmoudifar

Volume 4, Issue 1 , Summer and Autumn 2016, Pages 37-51

##### Abstract
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 ...  Read More

##### 5. STRONGLY DUO AND CO-MULTIPLICATION MODULES

S. Safaeeyan

Volume 4, Issue 1 , Summer and Autumn 2016, Pages 53-64

##### Abstract
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 ...  Read More

##### 6. SIGNED ROMAN DOMINATION NUMBER AND JOIN OF GRAPHS

A. Behtoei; E. Vatandoost; F. Azizi Rajol Abad

Volume 4, Issue 1 , Summer and Autumn 2016, Pages 65-77

##### Abstract
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.  Read More

##### 7. ARTINIANNESS OF COMPOSED LOCAL COHOMOLOGY MODULES

H. Saremi

Volume 4, Issue 1 , Summer and Autumn 2016, Pages 79-84

##### Abstract
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 ...  Read More