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Stable vectors in Moy–Prasad filtrations

Published online by Cambridge University Press:  09 February 2017

Jessica Fintzen
Affiliation:
Department of Mathematics, Harvard University, One Oxford Street, Cambridge, MA 02138, USA email fintzen@umich.edu Current address: Department of Mathematics, University of Michigan, 2074 East Hall, 530 Church St, Ann Arbor, MI 48109, USA
Beth Romano
Affiliation:
Department of Mathematics, Boston College, 140 Commonwealth Avenue, Chestnut Hill, MA 02467, USA email blr24@dpmms.cam.ac.uk Current address: Department of Pure Mathematics and Mathematical Statistics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WB, UK

Abstract

Let $k$ be a finite extension of $\mathbb{Q}_{p}$, let ${\mathcal{G}}$ be an absolutely simple split reductive group over $k$, and let $K$ be a maximal unramified extension of $k$. To each point in the Bruhat–Tits building of ${\mathcal{G}}_{K}$, Moy and Prasad have attached a filtration of ${\mathcal{G}}(K)$ by bounded subgroups. In this paper we give necessary and sufficient conditions for the dual of the first Moy–Prasad filtration quotient to contain stable vectors for the action of the reductive quotient. Our work extends earlier results by Reeder and Yu, who gave a classification in the case when $p$ is sufficiently large. By passing to a finite unramified extension of $k$ if necessary, we obtain new supercuspidal representations of ${\mathcal{G}}(k)$.

Type
Research Article
Copyright
© The Authors 2017 

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