On relative cuspidality
Abstract
Let be a symmetric pair of reductive groups over a -adic field with , attached to the involution . Under the assumption that there exists a maximally -split torus in , which is anisotropic modulo its intersection with the split component of , we extend Beuzart-Plessis' proof of existence of cuspidal representations, and prove that admits strongly relatively cuspidal representations. This confirms expectations of Kato and Takano.
Cite
@article{arxiv.2506.08393,
title = {On relative cuspidality},
author = {Nadir Matringe},
journal= {arXiv preprint arXiv:2506.08393},
year = {2026}
}
Comments
Main theorem wrong. (GL4n,Sp4n) provides a counter-example due to Lapid-Offen's classification of relative discrete series: none is strongly relatively cuspidal but there are G^- elliptic tori. Mistake in Section 7: \mu cannot be chosen uniform with respect to all parabolics. The first 6 sections might help prove existence of relatively cuspidal representations, but we did not find how