Multiplicities of fields of values of conjugacy classes in finite groups

Abstract

Given a group $G$ we write $h(G)$ to denote the maximum number of times that a field extension of $\mathbb{Q}$ appears as the field of values of a conjugacy class of a group. In this work, we prove that $|G|$ is bounded in terms of $h(G)$. Moreover, we classify the groups with $h(G)\leq 3$.