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Bibliographic Details
Main Authors: Corson, Jon M., Lee, Evan M.
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2502.18355
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author Corson, Jon M.
Lee, Evan M.
author_facet Corson, Jon M.
Lee, Evan M.
contents One of the advantages of working with Alexander-Spanier-Čech type cohomology theory is the continuity property: For inverse systems of sufficiently well-behaved spaces, the result of taking the cohomology of their limit is a direct limit of their cohomologies. However, Čech cohomology natively works with presheaves of modules rather than modules themselves. We define the notion of a system of presheaves for an inverse system of topological spaces, and show that, under the same circumstances as the ordinary continuity property, a suitable limit of the system provides the Čech cohomology of the inverse limit of the spaces. We then show one application of this result in comparing the cohomology of an inverse limit of finite groups to that of the inverse limit of their classifying spaces.
format Preprint
id arxiv_https___arxiv_org_abs_2502_18355
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An Expansion of the Continuity Property
Corson, Jon M.
Lee, Evan M.
Algebraic Topology
18G30, 18G60, 10J06, 22C05, 55N05
One of the advantages of working with Alexander-Spanier-Čech type cohomology theory is the continuity property: For inverse systems of sufficiently well-behaved spaces, the result of taking the cohomology of their limit is a direct limit of their cohomologies. However, Čech cohomology natively works with presheaves of modules rather than modules themselves. We define the notion of a system of presheaves for an inverse system of topological spaces, and show that, under the same circumstances as the ordinary continuity property, a suitable limit of the system provides the Čech cohomology of the inverse limit of the spaces. We then show one application of this result in comparing the cohomology of an inverse limit of finite groups to that of the inverse limit of their classifying spaces.
title An Expansion of the Continuity Property
topic Algebraic Topology
18G30, 18G60, 10J06, 22C05, 55N05
url https://arxiv.org/abs/2502.18355