A note on non-inner automorphism conjecture

TL;DR

This paper proves the existence of non-inner automorphisms of order p in certain finite p-groups, confirming the non-inner automorphism conjecture for groups of specific coclasses and generator conditions.

Contribution

It establishes the non-inner automorphism conjecture for finite p-groups of coclass 4 and 5, and identifies conditions for automorphisms in 2-generator p-groups.

Findings

Existence of non-inner automorphisms of order p in 2-generator p-groups for p≥5.

Validation of the conjecture for groups of coclass 4 and 5.

Automorphisms fixing specific subgroup elements in certain p-groups.

Abstract

In this paper we prove that every $2$-generator finite $p$-group $G$ has a non-inner automorphism of order $p$ leaving $G^p\gamma_4(G)$ elementwise fixed ($p\ge 5$). Moreover, we prove a $2$-generator finite $3$-group satisfying $|\Omega_1(Z_2(G))|=p^2$ has a non-inner automorphism of order $p$ leaving $G^p\gamma_3(G)$ elementwise fixed. As a consequence we prove the non-inner automorphism conjecture for every finite $p$-group of coclass $4$ ($p\ge 3$), and coclass $5$ ($p\ge 5$).