$h$-topology for rigid spaces and an application to $p$-adic Simpson correspondence
Hanlin Cai, Zeyu Liu
TL;DR
This work develops the $h$-topology for rigid spaces and uses it to extend the $p$-adic Simpson correspondence to singular proper rigid spaces over $C$. By proving foundational flatness results, a rigid-analytic platification by blowups, and Zariski-type refinements of fppf covers, it builds a robust descent framework for vector bundles and Higgs bundles. Through simplicial/hypercover techniques, it reduces singular cases to smooth ones and establishes an equivalence between pro-étale vector bundles and Higgs bundles on the $h$-site, together with a cohomology comparison that aligns pro-étale and Higgs cohomology. The results significantly generalize Heuer’s correspondence and open avenues for non-smooth non-abelian $p$-adic Hodge theory, including a structured cohomological dimension and descent theory for Higgs data on the $h$-site.
Abstract
In this paper, we study the $h$-topology for rigid spaces. Along the way, we establish several foundational results on morphisms of rigid spaces: we prove generic flatness and openness of the flat locus in the rigid setting, and we show that (for affinoid rigid spaces) strict transforms become flat after a blowup. Moreover, we show that any fppf cover admits a quasi-finite refinement and prove a version of Zariski's main theorem for rigid spaces. As an application, we deduce that for a proper rigid space $X$ over $C$, the category of pro-étale vector bundles on $X$ is equivalent to the category of Higgs bundles on the $h$-site of $X$, thereby generalizing Heuer's results to the singular setting.
