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We give a complete and irredundant list of the finite groups $G$ for which Aut$(G)$, acting naturally on $G$, has precisely $3$ orbits. There are 7 infinite families: one abelian, one non-nilpotent, three families of non-abelian $2$-groups…

Group Theory · Mathematics 2025-02-20 Stephen P. Glasby

By a result of Noritzsch, a finite solvable group whose non-linear character degrees have the same set of prime divisors is meta-abelian. In this note we investigate finite non-solvable groups whose non-linear character degrees have the…

Representation Theory · Mathematics 2026-04-14 Junying Guo , Yanjun Liu , Ziyi Wu , Di Xiao

Let $p$ be a prime number and suppose that every maximal subgroup of a finite group is either $p$-nilpotent or has prime index. Such group need not be $p$-solvable, and we study its structure by proving that only one nonabelian simple group…

Group Theory · Mathematics 2024-09-18 Antonio Beltrán , Changguo Shao

Let $G$ be a finite non-solvable group with solvable radical $Sol(G)$. The solvable graph $\Gamma_s(G)$ of $G$ is a graph with vertex set $G\setminus Sol(G)$ and two distinct vertices $u$ and $v$ are adjacent if and only if $\langle u, v…

Group Theory · Mathematics 2019-03-06 Parthajit Bhowal , Deiborlang Nongsiang , Rajat Kanti Nath

If $\mathscr{J}$ is a finite-dimensional nilpotent algebra over a finite field $\Bbbk$, the algebra group $P = 1+\mathscr{J}$ admits a (standard) supercharacter theory as defined by Diaconis and Isaacs. If $\mathscr{J}$ is endowed with an…

Representation Theory · Mathematics 2015-02-06 Carlos A. M. André , Pedro J. Freitas , Ana Margarida Neto

In this paper, we consider solvable groups that satisfy the two-prime hypothesis. We prove that if $G$ is such a group and $G$ has no nonabelian nilpotent quotients, then $|\cd G| \le 462,515$. Combining this result with the result from…

Group Theory · Mathematics 2010-10-20 James Hamblin , Mark L. Lewis

We determine the structure of the finite non-solvable groups of order divisible by $3$ all whose maximal subgroups of order divisible by $3$ are supersolvable. Precisely, we demonstrate that if $G$ is a finite non-solvable group satisfying…

Group Theory · Mathematics 2025-04-29 Antonio Beltrán , Changguo Shao

Supercharacter theory is developed by P. Diaconis and I. M. Isaacs as a natural generalization of the classical ordinary character theory. Some classical sums of number theory appear as supercharacters which are obtained by the action of…

Group Theory · Mathematics 2020-02-25 Hadiseh Saydi , Mohammad Reza Darafsheh , Ali Iranmanesh

In this paper, we prove Sp\"ath's Character Triple Conjecture for $p$-solvable groups. This is a conjecture proposed by Sp\"ath during the reduction process of Dade's Projective Conjecture to quasisimple groups. In addition, as suggested by…

Representation Theory · Mathematics 2021-11-04 Damiano Rossi

We investigate the finite groups $G$ for which $\chi(1)^{2}=|G:Z(\chi)|$ for all characters $\chi \in Irr(G)$ and $|cd(G)|=2$, where $cd(G)=\{\chi(1)| \chi \in Irr(G)\}$. We call such a group a GVZ-group with two character degrees. We…

Group Theory · Mathematics 2024-07-16 Nabajit Talukdar , Kukil Kalpa Rajkhowa

Given a finite group G, let cd(G) denote the set of degrees of the irreducible complex characters of G. The character degree graph of G is defined as the simple undirected graph whose vertices are the prime divisors of the numbers in cd(G),…

Group Theory · Mathematics 2018-09-28 Zeinab Akhlaghi , Carlo Casolo , Silvio Dolfi , Emanuele Pacifici , Lucia Sanus

Let $G$ be a finite group, and $\pi$ be a set of primes. The $\pi$-core $\mathbf{O}_\pi(G)$ is the unique maximal normal $\pi$-subgroup of $G$, and $b(G)$ is the largest irreducible character degree of $G$. In 2017, Qian and Yang proved…

Group Theory · Mathematics 2024-10-14 Zongshu Wu , Yong Yang

The supercharacter theory is constructed for the parabolic subgroups of $\mathrm{GL}(n,\Fq)$ with blocks of orders less or equal to two. The author formulated the hypotheses on construction of a supercharacter theory for an arbitrary…

Representation Theory · Mathematics 2017-09-19 A. N. Panov

This paper classifies the factorizations of almost simple groups with a factor having at least two nonsolvable composition factors. This together with a previous classification result of the authors reduces the factorization problem of…

Group Theory · Mathematics 2019-04-02 Cai Heng Li , Binzhou Xia

We prove that $\mathrm{SL}_3(\mathbb{Z})$ contains a non-split sharply 2-transitive subgroup, answering a question of Glasner and Gulko. We also prove that $\mathrm{SL}_4(\mathbb{Z})$ contains a non-split sharply 3-transitive subgroup, but…

Group Theory · Mathematics 2026-04-09 Marco Amelio , Simon André

Let $\lambda(G)$ be the maximum number of subgroups in an irredundant covering of the finite group $G$. We prove that if $G$ is a group with $\lambda(G) \leqslant 6$, then $G$ is supersolvable. We also describe the structure of the groups…

Group Theory · Mathematics 2020-03-16 Igor Lima , Raimundo Bastos , José R. Rogério

Finite $p$-groups with a unique $\mathcal{A}_2$-subgroup are classified up to isomorphism. A problem proposed by Berkovich and Janko is solved.

Group Theory · Mathematics 2022-03-16 Jixia Gao , Dandan Zhang , Haipeng Qu

In this paper we show that there is an infinite number of finite groups with two relative subgroup commutativity degrees. Also, we indicate a sufficient condition such that a finite group has at least three relative subgroup commutativity…

Group Theory · Mathematics 2018-01-30 Mihai-Silviu Lazorec , Marius Tărnăuceanu

Two finitely generated groups have the same set of finite quotients if and only if their profinite completions are isomorphic. Consider the map which sends (the isomorphism class of) an S-arithmetic group to (the isomorphism class of) its…

Group Theory · Mathematics 2011-10-25 Menny Aka

In this paper we consider finite groups G satisfying the following condition: G has two columns in its character table which differ by exactly one entry. It turns out that such groups exist and they are exactly the finite groups with a…

Group Theory · Mathematics 2016-05-06 Mariagrazia Bianchi , Marcel Herzog