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INTERTWINING SEMISIMPLE CHARACTERS FOR $p$-ADIC CLASSICAL GROUPS

Published online by Cambridge University Press:  16 July 2018

DANIEL SKODLERACK
Affiliation:
School of Mathematics, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK email skodlerack-daniel@web.de
SHAUN STEVENS
Affiliation:
School of Mathematics, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK email Shaun.Stevens@uea.ac.uk

Abstract

Let $G$ be an orthogonal, symplectic or unitary group over a non-archimedean local field of odd residual characteristic. This paper concerns the study of the “wild part” of an irreducible smooth representation of $G$, encoded in its “semisimple character”. We prove two fundamental results concerning them, which are crucial steps toward a complete classification of the cuspidal representations of $G$. First we introduce a geometric combinatorial condition under which we prove an “intertwining implies conjugacy” theorem for semisimple characters, both in $G$ and in the ambient general linear group. Second, we prove a Skolem–Noether theorem for the action of $G$ on its Lie algebra; more precisely, two semisimple elements of the Lie algebra of $G$ which have the same characteristic polynomial must be conjugate under an element of $G$ if there are corresponding semisimple strata which are intertwined by an element of $G$.

Type
Article
Copyright
© 2018 Foundation Nagoya Mathematical Journal

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Footnotes

This research was funded by EPSRC grant EP/H00534X/1.

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