dorsal/arxiv
View Schemap-Curvature and Non-Abelian Cohomology
| Authors | Yeuk Hay Joshua Lam, Daniel Litt |
|---|---|
| Categories | |
| ArXiv ID | 2601.07933vv1 |
| URL | https://arxiv.org/abs/2601.07933 |
| License | http://creativecommons.org/licenses/by/4.0/ |
Abstract
Let $X\to S$ be a smooth projective morphism. Katz proved the Grothendieck-Katz $p$-curvature conjecture for the Gauss-Manin connection on the $i$-th cohomology of $X/S$: if its $p$-curvature vanishes mod $p$ for infinitely many $p$, then the action of $\pi_1(S,s)$ on $H^i(X_s, \mathbb{Z})$ factors through a finite group. We prove a non-abelian analogue of this statement: if the $p$-curvature of the isomonodromy foliation on the moduli of flat bundles of rank $r$ on $X/S$ vanishes mod $p$ for infinitely many $p$, then the action of $\pi_1(S,s)$ on the rank $r$ integral characters of $\pi_1(X_s)$ factors through a finite group. We deduce many new cases of the Bost/Ekedahl--Shepherd-Barron--Taylor conjecture. The proofs rely on a non-abelian version of Katz's formula, and a non-abelian version of the Hodge index theorem.
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"abstract": "Let $X\\to S$ be a smooth projective morphism. Katz proved the Grothendieck-Katz $p$-curvature conjecture for the Gauss-Manin connection on the $i$-th cohomology of $X/S$: if its $p$-curvature vanishes mod $p$ for infinitely many $p$, then the action of $\\pi_1(S,s)$ on $H^i(X_s, \\mathbb{Z})$ factors through a finite group. We prove a non-abelian analogue of this statement: if the $p$-curvature of the isomonodromy foliation on the moduli of flat bundles of rank $r$ on $X/S$ vanishes mod $p$ for infinitely many $p$, then the action of $\\pi_1(S,s)$ on the rank $r$ integral characters of $\\pi_1(X_s)$ factors through a finite group. We deduce many new cases of the Bost/Ekedahl--Shepherd-Barron--Taylor conjecture.\n The proofs rely on a non-abelian version of Katz\u0027s formula, and a non-abelian version of the Hodge index theorem.",
"arxiv_id": "2601.07933",
"authors": [
"Yeuk Hay Joshua Lam",
"Daniel Litt"
],
"categories": [
"math.AG",
"math.NT"
],
"license": "http://creativecommons.org/licenses/by/4.0/",
"title": "p-Curvature and Non-Abelian Cohomology",
"url": "https://arxiv.org/abs/2601.07933",
"version": "v1"
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