Branching rules for irreducible depth-zero supercuspidal representations of $\mathrm{SL}(2,F)$, when $F$ has residual characteristic $2$

Abstract

We give the decomposition into irreducible representations of the restriction to a maximal compact subgroup of any irreducible depth-zero supercuspidal representation of $\mathrm{SL}(2,F)$ when $F$ is a local nonarchimedean field of residual characteristic two. We furthermore provide explicit constructions of these irreducible components in terms of nilpotent orbits, proving a representation-theoretic analogue of the local character expansion that holds even in the wild case of characteristic two.