Fields of Fractions in Rigid Geometry
Jiahong Yu
TL;DR
The paper shows that in rigid geometry, the normalization of an affinoid integral K-algebra can be reconstructed from its field of fractions by intersecting all maximal discrete valuation rings, enabling a fully faithful link between normal affinoid domains and field extensions of K. This provides a p-adic analogue of the Riemann Hebbarkeitssatz and yields practical criteria for finiteness of morphisms, along with applications to prismatic cohomology and dagger algebras. The approach hinges on valuation-theoretic reconstruction and Nagata/excellence properties of affinoid algebras, bridging birational-like data with analytic structure in the non-Archimedean setting.
Abstract
Let $A$ be an affinoid integral domain over a non-Archimedean field $K$, and let $L$ be its field of fractions. We prove that the normalization of $A$ can be reconstructed from $L$ by taking the intersection of all maximal discrete valuation subrings. As a corollary, taking the field of fractions induces a fully faithful functor from the category of normal affinoid integral domains over $K$ to the category of field extensions of $K$. This provides another $p$-adic analogue of the Riemann Hebbarkeitssatz.
