A theorem on meromorphic descent and the specialization of the pro-étale fundamental group
Abstract
Given a Noetherian formal scheme $\hat X$ over ${\rm Spf}(R)$, where $R$ is a complete DVR, we first prove a theorem of meromorphic descent along a possibly infinite cover of $\hat{X}$. Using this we construct a specialization functor from the category of continuous representations of the pro-étale fundamental group of the special fiber to the category of $F$-divided sheaves on the generic fiber. This specialization functor partially recovers the specialization functor of the étale fundamental groups. We also express the pro-étale fundamental group of a connected scheme $X$ of finite type over a field as coproducts and quotients of the free group and the étale fundamental groups of the normalizations of the irreducible components of $X$ and those of its singular loci.
- Publication:
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arXiv e-prints
- Pub Date:
- March 2021
- arXiv:
- arXiv:2103.11543
- Bibcode:
- 2021arXiv210311543L
- Keywords:
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- Mathematics - Algebraic Geometry;
- Mathematics - Algebraic Topology;
- Mathematics - Category Theory;
- Mathematics - Number Theory