Two results on character codegrees

Abstract

Let $G$ be a finite group and $\mathrm{\text{Irr}}(G)$ be the set of irreducible characters of $G$. The codegree of an irreducible character $\chi$ of the group $G$ is defined as $\mathrm{\text{cod}}(\chi )=|G:\mathrm{\text{ker}}(\chi )|/\chi (1)$. In this paper, we study two topics related to the character codegrees. The first result is related to the prime graph of character codegrees and we show that the codegree prime graphs of several classes of groups can be characterized only by graph theoretical terms. The second result is about the $p$-parts of the codegrees and character degrees.