2017/08/25 by Florian Herzig, Daniel Le, Stefano Morra · 1 citation
Mathematics · #Algebraic Geometry and Number Theory #Advanced Algebra and Geometry #Homotopy and Cohomology in Algebraic Topology
paper · doi:10.1112/s0010437x17007357
Suppose that F/F+ is a CM extension of number fields in which the prime p splits completely and every other prime is unramified. Fix a place w|p of F . Suppose that r:Gal(F/F)→ GL3(\mathbbFp) is a continuous irreducible Galois representation such that r|_Gal(Fw/Fw) is upper-triangular, maximally non-split, and generic. If r is automorphic, and some suitable technical conditions hold, we show that r|_Gal(Fw/Fw) can be recovered from the GL3(Fw) -action on a space of mod p automorphic forms on a compact unitary group. On the way we prove results about weights in Serre’s conjecture for r , show the existence of an ordinary lifting of r , and prove the freeness of certain Taylor–Wiles patched modules in this context. We also show the existence of many Galois representations r to which our main theorem applies.