Classification of metric fibrations

Fuente: arXiv
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Main Author: Asao, Yasuhiko
Format: Preprint
Published: 2023
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author Asao, Yasuhiko
author_facet Asao, Yasuhiko
contents In this paper, we study `a fibration of metric spaces' that was originally introduced by Leinster in the study of the magnitude and called metric fibrations. He showed that the magnitude of a metric fibration splits into the product of those of the fiber and the base, which is analogous to the Euler characteristic and topological fiber bundles. His idea and our approach is based on Lawvere's suggestion of viewing a metric space as an enriched category. Actually, the metric fibration turns out to be the restriction of the enriched Grothendieck fibrations to metric spaces. We give a complete classification of metric fibrations by several means, which is parallel to that of topological fiber bundles. That is, the classification of metric fibrations is reduced to that of `principal fibrations', which is done by the `1-Cech cohomology' in an appropriate sense. Here we introduce the notion of torsors in the category of metric spaces, and the discussions are analogous to the sheaf theory. Further, we can define the `fundamental group $π^m_1(X)$' of a metric space $X$, which is a group object in metric spaces, such that the conjugation classes of homomorphisms $Hom(π^m_1(X), G)$ corresponds to the isomorphism classes of `principal $G$-fibrations' over $X$. Namely, it is classified like topological covering spaces.
format Preprint
id arxiv_https___arxiv_org_abs_2307_04387
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Classification of metric fibrations
Asao, Yasuhiko
Algebraic Topology
Category Theory
Metric Geometry
In this paper, we study `a fibration of metric spaces' that was originally introduced by Leinster in the study of the magnitude and called metric fibrations. He showed that the magnitude of a metric fibration splits into the product of those of the fiber and the base, which is analogous to the Euler characteristic and topological fiber bundles. His idea and our approach is based on Lawvere's suggestion of viewing a metric space as an enriched category. Actually, the metric fibration turns out to be the restriction of the enriched Grothendieck fibrations to metric spaces. We give a complete classification of metric fibrations by several means, which is parallel to that of topological fiber bundles. That is, the classification of metric fibrations is reduced to that of `principal fibrations', which is done by the `1-Cech cohomology' in an appropriate sense. Here we introduce the notion of torsors in the category of metric spaces, and the discussions are analogous to the sheaf theory. Further, we can define the `fundamental group $π^m_1(X)$' of a metric space $X$, which is a group object in metric spaces, such that the conjugation classes of homomorphisms $Hom(π^m_1(X), G)$ corresponds to the isomorphism classes of `principal $G$-fibrations' over $X$. Namely, it is classified like topological covering spaces.
title Classification of metric fibrations
topic Algebraic Topology
Category Theory
Metric Geometry
url https://arxiv.org/abs/2307.04387