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Bibliographic Details
Main Authors: Loeh, Clara, Witzig, Johannes
Format: Preprint
Published: 2022
Subjects:
Online Access:https://arxiv.org/abs/2209.12971
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Table of Contents:
  • Functorial semi-norms on singular homology measure the "size" of homology classes. A geometrically meaningful example is the $\ell^1$-semi-norm. However, the $\ell^1$-semi-norm is not universal in the sense that it does not vanish on as few classes as possible. We show that universal finite functorial semi-norms do exist on singular homology on the category of topological spaces that are homotopy equivalent to finite CW-complexes. Our arguments also apply to more general settings of functorial semi-norms.