Forgotten characters

Abstract

A partial permutation of $[n] := \{1,\dots,n\}$ is a bijection $g: I \to J$ between two subsets $I,J \subseteq [n]$. Given a partial permutation $g$ of $[n]$, let $a_g \in \mathbb{C}[\mathfrak{S}_n]$ be the group algebra sum of those permutations $w \in \mathfrak{S}_n$ which extend $g$. Informally, a partial permutation $g$ is obtained by forgetting some data in a genuine permutation. The forgotten symmetric functions are the least-studied of the six `standard' bases for the ring of symmetric functions. We show that forgotten symmetric functions arise naturally in class function evaluations on partial permutations.