On typical representations for depth-zero components of split classical groups

Abstract:

Let $\mathbf {G}$ be a split classical group over a non-Archimedean local field $F$ with the cardinality of the residue field $q_F>5$. Let $M$ be the group of $F$-points of a Levi factor of a proper $F$-parabolic subgroup of $\mathbf {G}$. Let $[M, \sigma _M]_M$ be an inertial class such that $\sigma _M$ contains a depth-zero Moy–Prasad type of the form $(K_M, \tau _M)$, where $K_M$ is a hyperspecial maximal compact subgroup of $M$. Let $K$ be a hyperspecial maximal compact subgroup of $\mathbf {G}(F)$ such that $K$ contains $K_M$. In this article, we classify $\mathfrak {s}$-typical representations of $K$. In particular, we show that the $\mathfrak {s}$-typical representations of $K$ are precisely the irreducible subrepresentations of $\operatorname {ind}_J^K\lambda$, where $(J, \lambda )$ is a level-zero $G$-cover of $(K\cap M, \tau _M)$.