Number Theory Seminar

Seminar information archive ~04/28Next seminarFuture seminars 04/29~

Date, time & place Wednesday 17:00 - 18:00 117Room #117 (Graduate School of Math. Sci. Bldg.)
Organizer(s) Naoki Imai, Shane Kelly

2023/05/10

17:00-18:00   Room #117 (Graduate School of Math. Sci. Bldg.)
Guy Henniart (Paris-Sud University)
Swan exponent of Galois representations and fonctoriality for classical groups over p-adic fields (English)
[ Abstract ]
This is joint work with Masao Oi in Kyoto. Let F be a p-adic field for some prime number p,
F^ac an algebraic closure of F, and G_F the Galois group of F^ac/F. A continuous finite dimensional
representation σ (on a complex vector space W) has a Swan exponent s(σ), a non-negative integer
which measures how "wildly ramified" σ is. Langlands functoriality makes it of interest
to compare s(σ) and s(r o σ) when r is an algebraic representation of Aut_C(W). The first cases
for r are the determinant, the adjoint representation, the symmetric square representation and
the alternating square representation. I shall give some relations (inequalities mostly, with
equality in interesting cases) between the Swan exponents of those representations r o σ. I shall
also indicate how such relations can be used to explicit the local Langlands correspondence of
Arthur for some simple cuspidal representations of split classical groups over F.