A note on Jacquet functors and ordinary parts

Abstract

In this note we relate Emerton's Jacquet functor $J_P$ to his ordinary parts functor $\operatorname{Ord} _P$, by computing the χ-eigenspaces $\operatorname{Ord} ^{\chi }_P$ for central characters χ. This fills a small gap in the literature. One consequence is a weak adjunction property for \textit {unitary} characters χ appearing in $J_P$, with potential applications to local-global compatibility in the $p$-adic Langlands program in the ordinary case.