arXiv subjects

Sayyed Heidar Jafari

Publications and source records attributed to Sayyed Heidar Jafari.

5 recordsLinked to original sources

arXiv2024

Some factorization properties of idealization in commutative rings with zero divisors

We study some factorization properties of the idealization $R \mathop{(\! + \! )} M$ of a module $M$ in a commutative ring $R$ which is not necessarily a domain. We show that $R \mathop{(\! + \! )} M$ is ACCP if and only if $R$ is ACCP and $M$ satisfies ACC on its cyclic submodules. We give an example to show that the BF property is not necessarily preserved in idealization, and give some conditions under which $R \mathop{(\! + \! )} M$ is a BFR. We also characterize the idealization rings which are UFRs.

math.AC↗

arXiv2022

Power graphs of all nilpotent groups

The directed power graph $\vec{\mathcal G}(\mathbf G)$ of a group $\mathbf G$ is the simple digraph with vertex set $G$ such that $x\rightarrow y$ if $y$ is a power of $x$. The power graph $\mathcal G(\mathbf G)$ of the group $\mathbf G$ is the underlying simple graph. In this paper, we prove that Prüfer group is the only nilpotent group whose power graph does not determine the directed power graph up to isomorphism. Also, we present a group $\mathbf G$ with quasicyclic torsion subgroup that is determined by its power graph up to isomorphism, i.e. such that $\mathcal G(\mathbf H)\cong\mathcal G(\mathbf G)$ implies $\mathbf H\cong \mathbf G$ for any group $\mathbf H$.

math.GR↗

arXiv2019

A description of automorphism group of power graphs of finite groups

The power graph of a group is the graph whose vertex set is the set of nontrivial elements of group, two elements being adjacent if one is a power of the other. We introduce some way for find the automorphism groups of some graphs. As an application We describe the full automorphism group of the power graph of all finite groups. Also we obtain the full automorphism group of power graph of abelian, homocyclic and nilpotent groups

math.GR↗

arXiv2019

The energy and spectrum of non commuting graph

Let G be a non-abelian group and Z(G) be the center of G. The non-commuting graph Γ(G) of G is a graph with vertex set is non central elements of G and two vertices x, y are adjacent if and only if they are commute. In this paper we calculate the energy, Laplacian energy and spectrum of non-commuting graph of dihedral group D2n. Also we will obtain the energy of non-commuting graph of D2n \times D2n and G \times H, where G is a non-abelian finite group and H is an abelian finite group

math.GR↗

arXiv2019

The diameter of proper power graphs of alternating groups

The power graph of finite group G is a simple graph whose vertex set is G and two distinct elements a and b are adjacent if and only if one of them is a power of the other. The proper power graph of G is a graph which is obtained by deleting the identity vertex (the identity element of G). In this paper, we improve the diameter bound of proper power graph of alternating group of degree n which the graph is connected. We show that the diameter of An is between 6 and 11, if the n at least 51. We also describe a number of short paths in these power graphs.

math.GR↗