Parametrizing nilpotent orbits via Bruhat-Tits theory

Abstract

Let $k$ denote a field with nontrivial discrete valuation. We assume that $k$ is complete with perfect residue field. Let $G$ be the group of $k$-rational points of a reductive, linear algebraic group defined over $k$. Let $\gg$ denote the Lie algebra of $G$. Fix $r \in \R$. Subject to some restrictions, we show that the set of distinguished degenerate Moy-Prasad cosets of depth $r$ (up to an equivalence relation) parametrizes the nilpotent orbits in $\gg$.