Moduli of local shtukas and Harris’s conjecture

Abstract

We prove, under a certain assumption of “Hodge-Newton reducibility”, a strong form of a conjecture of Harris on the cohomology of moduli spaces of mixed-characteristic local shtukas for GLn. Our strategy is roughly based on a previous strategy developed by Mantovan in the setting of p-divisible groups, but the arguments are completely different. In particular, we reinterpret and generalize the Hodge-Newton filtration of a p-divisible group in terms of modified vector bundles on the Fargues-Fontaine curve. We also compute the dualizing complex and compactly supported étale cohomology of any positive Banach-Colmez space over any base; this should be of independent interest.