Throughout this paper, every groups are finite. The prime graph of a group $G$ is denoted by $Gamma(G)$. Also $G$ is called recognizable by prime graph if for every finite group $H$ with $Gamma(H) = Gamma(G)$, we conclude that $Gcong H$. Until now, it is proved that if $k$ is an odd number and $p$ is an odd prime number, then $PGL(2,p^k)$ is recognizable by prime graph. So if $k$ is even, the r...

If p is an odd prime, then the Gupta-Sidki group Gp is an infinite 2-generated p-group. It is defined in a recursive manner as a particular subgroup of the automorphism group of a regular tree of degree p. In this note, we make two observations concerning the irreducible representations of the group algebra K[Gp] with K an algebraically closed field. First, when charK 6= p, we obtain a lower bo...

We give a criterion for an HNN extension of a finite p-group to be residually p. 1. Statement of the Main Results By an HNN pair we mean a pair (G,φ) where G is a group and φ : A → B is an isomorphism between subgroups A and B of G. Given such an HNN pair (G,φ) we consider the corresponding HNN extension G∗ = 〈G, t | t−1at = φ(a), a ∈ A〉 of G, which we denote, by slight abuse of notation, as G∗...

We prove that every finite-dimensional representation of a finite group over field characteristic p admits resolution by p-permutation modules. The proof involves reformulation in terms derived categories.

We investigate the braid group representations arising from categories of representations of twisted quantum doubles of finite groups. For these categories, we show that the resulting braid group representations always factor through finite groups, in contrast to the categories associated with quantum groups at roots of unity. We also show that in the case of p-groups, the corresponding pure br...

This thesis has three goals related to the automorphism groups of finite p-groups. The primary goal is to provide a complete proof of a theorem showing that, in some asymptotic sense, the automorphism group of almost every finite p-group is itself a p-group. We originally proved this theorem in a paper with Martin; the presentation of the proof here contains omitted proof details and revised ex...

In this article we introduce and study the concept of characteristic degree of a subgroup in a finite group. We define the characteristic degree of a subgroup H in a finite group G as the ratio of the number of all pairs (h,α) ∈ H×Aut(G) such that h^α∈H, by the order of H × Aut(G), where Aut(G) is the automorphisms group of G. This quantity measures the probability that H can be characteristic ...

For a finite p-group P the following three conditions are equivalent: (a) to have a (proper) partition, that is, to be the union of some proper subgroups with trivial pairwise intersections; (b) to have a proper subgroup outside of which all elements have order p; (c) to be a semidirect product P = P1o ⟨φ⟩ where P1 is a subgroup of index p and φ is a splitting automorphism of order p of P1. It ...

In finite group theory, one of the most influential ideas is the notion of Sylow p-subgroup. It was used to classify many groups of finite order. Despite original intentions to use it with finite group, it was extended to study Lie group, which inspires recent development in p-compact group. Here, we will discuss some aspects of Sylow’s Subgroup Theorem. In particular, the focus is on a finite ...