The Fitting height of finite groups with a fixed-point-free automorphism satisfying an identity

Abstract

Motivated by classic theorems of Thompson and Berger on the Fitting height of finite groups with a fixed-point-free automorphism of coprime order, we conjecture that, for every non-zero polynomial $f(x) = a_0 + a_1 x + \cdots + a_d x^d \in \mathbb{Z}[x] $, there is an integer $k > 0$ with the following property. Let $G$ be a finite (solvable) group with a fixed-point-free automorphism $\alpha$ satisfying $\gcd(|G|,k)= 1$ and $$\{ g^{a_0} \cdot \alpha(g)^{a_1} \cdot \alpha^2(g)^{a_2} \cdots \alpha^d(g)^{a_d} | g \in G \} = \{1\}.$$ Then the Fitting height of $G$ is at most the number of irreducible factors of $f(x)$. We confirm the conjecture for a large family of polynomials with explicit constants $k$.