The local character expansion as branching rules: nilpotent cones and the case of
arXiv:2309.17213 · doi:10.2140/pjm.2024.329.259
Abstract
We show there exist representations of each maximal compact subgroup of the -adic group , attached to each nilpotent coadjoint orbit, such that every irreducible representation of , upon restriction to a suitable subgroup of , is a sum of these five representations in the Grothendieck group. This is a representation-theoretic analogue of the analytic local character expansion due to Harish-Chandra and Howe. Moreover, we show for general connected reductive groups that the wave front set of many irreducible positive-depth representations of are completely determined by the nilpotent support of their unrefined minimal -types.
32 pages; added references to recent related work of Henniart-Vignéras