On the potential automorphy and the local-global compatibility for the monodromy operators at $p \neq l$ over CM fields
Kojiro Matsumoto
TL;DR
The paper advances the study of local-global compatibility for GL_n over CM fields at p ≠ l by extending potential automorphy methods to higher dimensions and introducing a parity-based, monodromy-aware framework using parahoric levels. It develops a new approach to relate Weil–Deligne monodromy with automorphic realizations, enabling automatic compatibility at non-l places and a density-one set of primes, with unconditional Ramanujan results in dimension two. Through crystalline and ordinary automorphy lifting theorems and patching arguments, it establishes potential automorphy in self-dual and ordinary settings, and obtains applications to the purity of compatible $l$-adic Galois representations and Bloch–Kato Selmer groups. Overall, the work broadens the scope of automorphy-lifting techniques, connecting monodromy data to global automorphy in higher rank and more general weight regimes. It lays groundwork for further unifications of local and global Langlands correspondences in CM-field contexts.
Abstract
Let $F$ be a CM field. In this paper, we prove the local-global compatibility for cohomological cuspidal automorphic representations of $\mathrm{GL}_n(\mathbb{A}_F)$ at $p \neq l$ by using certain potential automorphy theorems in some cases including higher dimensional cases. Moreover, we also prove the Ramanujan conjecture for cohomological cuspidal automorphic representations of $\mathrm{GL}_2(\mathbb{A}_F )$.
