Paquets d'Arthur discrets pour un groupe classique p-adique
Abstract
In this paper we construct some packets of representations which have to correspond to relatively general Arthurs packets; this is for any classical group
G
over a p-adic field
F
. An Arthur's packet correspond to a map
ψ
from
W
F
×SL(2,C)×SL(2,C)
into the
L
-group of
G
. The packets we consider here have the property that the centralizer of
ψ
in the dual group is a finite groupe. Our construction is a combinatorial one which reduce the study of the representations in such a packet to tempered representation of eventualy smaller groups; in fact we give a precise description of the representations associated to
ψ
and a character of the centralizer of
ψ
in the L-group in the Grothendieck group. Stability properties follow easily from analogous properties for the tempered packet which enter the situation.