‎Let G be a finite group and Z(G) be the center of G‎. ‎For a subset A of G‎, ‎we define kG(A)‎, ‎the number of conjugacy classes of G that intersect A non-trivially‎. ‎In this paper‎, ‎we verify the structure of all finite groups G which satisfy the property kG(G-Z(G))=5, and classify them‎.

Let $G$ be a finite group. The automorphism $sigma$ of a group $G$ is said to be an absolute central automorphism, if for all $xin G$, $x^{-1}x^{sigma}in L(G)$, where $L(G)$ be the absolute centre of $G$. In this paper, we study  some properties of absolute central automorphisms of a given finite $p$-group.

Given a group G and an integer n ≥ 2 we construct a new group e K(G, n). Although this construction naturally occurs in the context of finding new invariants for complex algebraic surfaces, it is related to the theory of central extensions and the Schur multiplier. A surprising application is that Abelian groups of odd order possess naturally defined covers that can be computed from a given cov...

‎Suppose $n$ is a fixed positive integer‎. ‎We introduce the relative n-th non-commuting graph $Gamma^{n} _{H,G}$‎, ‎associated to the non-abelian subgroup $H$ of group $G$‎. ‎The vertex set is $Gsetminus C^n_{H,G}$ in which $C^n_{H,G} = {xin G‎ : ‎[x,y^{n}]=1 mbox{~and~} [x^{n},y]=1mbox{~for~all~} yin H}$‎. ‎Moreover‎, ‎${x,y}$ is an edge if $x$ or $y$ belong to $H$ and $xy^{n}eq y^{n}x$ or $x...

We generalise the concept of universal central extensions for perfect groups to arbitrary finite groups. This construction, called the semiversal central extension of the group, has the property that it contains every cover of this group as a subquotient.

The quotient of a biautomatic group by a subgroup of the center is shown to be biautomatic. The main tool used is the Neumann-Shapiro triangulation of S, associated to a biautomatic structure on Zn. As an application, direct factors of biautomatic groups are shown to be biautomatic. Biautomatic groups form a wide class of finitely presented groups with interesting geometric and computational pr...

conclusions the findings point to a relationship between neighborhood characteristics and obesity only in the azeri turks. however, educational level was more important than neighborhood quality in predicting the risk of obesity results three common neighborhood environments were identified: 1) modern-affluent, 2) central-high access and 3) marginal. these three factors explained 73.2% of the t...

conclusions it seems that there is no difference in the use of heparinized and normal saline solutions to prevent catheter occlusion of arterial and central venous pressure. patients and methods in the current randomized controlled trial, 100 patients, with an age range of 18 - 65 years of valve and coronary artery surgery were studied in rajaie heart center, tehran, iran. patients were randomi...