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Related papers: A survey on the Non-inner Automorphism Conjecture

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Let $G$ be a finite non-abelian $p$-group admitting cyclic center and $p$ be an odd prime. In this paper, we prove that if $C_{G}(Z(\gamma_{3}(G)G^{p}))\nleqslant\gamma_{3}(G)G^{p}$, then $G$ has a non-inner automorphism of order $p$.

Group Theory · Mathematics 2025-05-08 Xuesong Ma , Wei Xu

We prove a cohomological property for a class of finite $p$-groups introduced earlier by M. Y. Xu, which we call semi-abelian $p$-groups. This result implies that a semi-abelian $p$-group has non-inner automorphisms of order $p$, which…

Group Theory · Mathematics 2014-06-23 Mohammed T. Benmoussa , Yassine Guerboussa

We study groups having the property that every non-abelian subgroup contains its centralizer. We describe various classes of infinite groups in this class, and address a problem of Berkovich regarding the classification of finite $p$-groups…

Group Theory · Mathematics 2016-06-07 Costantino Delizia , Heiko Dietrich , Primoz Moravec , Chiara Nicotera

It is shown that if G is a finite p-group of coclass 2 with p > 2, then G has a noninner automorphism of order p.

Group Theory · Mathematics 2019-02-20 S. Fouladi , R. Orfi

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…

Group Theory · Mathematics 2007-11-20 Geir T. Helleloid

An automorphism of a group is called outer if it is not an inner automorphism. Let $G$ be a finite $p$-group. Then for every outer $p$-automorphism $\phi$ of $G$ the subgroup $C_G(\phi)=\{x\in G \;|\; x^\phi=x\}$ has order $p$ if and only…

Group Theory · Mathematics 2013-07-23 Alireza Abdollahi , S. Mohsen Ghoraishi

For each prime $p$ we construct a family $\{G_i\}$ of finite $p$-groups such that $|\Aut (G_i)|/|G_i|$ goes to $0$, as $i$ goes to infinity. This disproves a well-known conjecture that $|G|$ divides $|\Aut(G)|$ for every non-abelian finite…

Group Theory · Mathematics 2014-06-25 Jon Gonzalez-Sanchez , Andrei Jaikin-Zapirain

We determine the structure of automorphism group or each nonsplit metacyclic 2-group. This completes the work on automorphism groups of metacyclic $p$-groups.

Group Theory · Mathematics 2017-06-27 Haimiao Chen

We describe the autotopism group Atp(G) of any abelian group G as being a semidirect product of its automorphism group Aut(G) and G^2. We then provide the subgroup structure of Atp(G) when G is a finite cyclic group.

Group Theory · Mathematics 2012-01-30 Lucien Clavier

It is well known that every finite subgroup of automorphism group of polynomial algebra of rank 2 over the field of zero characteristic is conjugated with a subgroup of linear automorphisms. We prove that it is not true for an arbitrary…

Group Theory · Mathematics 2015-01-13 Valeriy G. Bardakov , Mikhail V. Neshchadim

We prove that the automorphism group of an arbitrary non-abelian free group is complete. It generalizes the result by J.Dyer and E.Formanek (1975) stating the completeness of automorphism group of finitely generated free groups. Using the…

Group Theory · Mathematics 2007-05-23 Vladimir Tolstykh

For any right-angled Artin group, we show that its outer automorphism group contains either a finite-index nilpotent subgroup or a nonabelian free subgroup. This is a weak Tits alternative theorem. We find a criterion on the defining graph…

Group Theory · Mathematics 2009-10-27 Matthew B. Day

We prove the Alperin-McKay Conjecture for all $p$-blocks of finite groups with metacyclic, minimal non-abelian defect groups. These are precisely the metacyclic groups whose derived subgroup have order $p$. In the special case $p=3$, we…

Representation Theory · Mathematics 2014-03-21 Benjamin Sambale

In this paper, we describe the automorphism group of semidirect product of two groups that fixes the non-normal subgroup of it. We have computed these automorphisms for the non-abelian metacyclic $p$-group and non-abelian $p$-groups $(p\ge…

Group Theory · Mathematics 2021-07-09 Ratan Lal , Vipul Kakkar

Bergman has given the following abstract characterisation of the inner automorphisms of a group $G$: they are exactly those automorphisms of $G$ which can be extended functorially along any homomorphism $G \rightarrow H$ to an automorphism…

Category Theory · Mathematics 2019-07-25 Richard Garner

This survey on the automorphism groups of finite p-groups focuses on three major topics: explicit computations for familiar finite p-groups, such as the extraspecial p-groups and Sylow p-subgroups of Chevalley groups; constructing p-groups…

Group Theory · Mathematics 2007-05-23 Geir T. Helleloid

There are several examples in the literature of finite non-abelian $p$-groups whose automorphism group is abelian. For some time only examples that were special $p$-groups were known, until Jain and Yadav [JY12] and Jain, Rai and Yadav…

Group Theory · Mathematics 2013-09-13 A. Caranti

Let $G$ be a finite $p$-group of order $p^5$, where $p$ is a prime. We give necessary and sufficient conditions on $G$ such that $G$ has a non-inner class-preserving automorphism. As a consequence, we give short and alternate proofs of…

Group Theory · Mathematics 2014-07-23 Mahak Sharma , Deepak Gumber

We give elementary proofs of the following two theorems on automorphisms of a finite group G: (1) An automorphism of G is inner if and only if it extends to an automorphism of every finite group containing G. (2) There exists a finite…

Group Theory · Mathematics 2024-05-07 Benjamin Sambale

(withdrawn.) For every lambda we give an explicit construction of an Abelian group with no non-trivial automorphisms. In particular the group absolutely has no non-trivial automorphisms, hence is absolutely indecomposable. Earlier we knew a…

Logic · Mathematics 2019-09-10 Saharon Shelah