Local-global compatibility for regular algebraic cuspidal automorphic representation when $\ell \neq p$

Abstract

We prove the compatibility of local and global Langlands correspondences for $GL_n$ up to semisimplification for the Galois representations constructed by Harris-Lan-Taylor-Thorne and Scholze. More precisely, let $r_p(\pi)$ denote an $n$-dimensional $p$-adic representation of the Galois group of a CM field $F$ attached to a regular algebraic cuspidal automorphic representation $\pi$ of $GL_n(\mathbb{A}_F)$. We show that the restriction of $r_p(\pi)$ to the decomposition group of a place $v\nmid p$ of $F$ corresponds up to semisimplification to $rec(\pi_v)$, the image of $\pi_v$ under the local Langlands correspondence. Furthermore, we can show that the monodromy of the associated Weil-Deligne representation of $.r_p(\pi)|_{G_{F_v}}$ is `more nilpotent' than the monodromy of $rec(\pi_v)$.