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Bibliographic Details
Main Authors: Gruner, Emma, Reimann, Jan
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2602.00940
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author Gruner, Emma
Reimann, Jan
author_facet Gruner, Emma
Reimann, Jan
contents By reformulating the classical proof as a Baire Category argument, we show that Besicovitch's Theorem in Cantor space is provable in $ACA_0$, and additionally that the witnessing subset is computable from one jump of the original set. We show that the necessary formulation of Baire Category, which we call Baire Category Theorem for Closed Sets (BCTC), is equivalent to $ACA_0$, contrasting with previous results on the reverse math strength of Baire Category variants. We also examine the implications of BCTC for more general monotone functions on closed sets, and explore how changing the representation of a closed set affects the reverse math strength of its measure regularity properties.
format Preprint
id arxiv_https___arxiv_org_abs_2602_00940
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Baire Category Approach to Besicovitch's Theorem and Measure Regularity
Gruner, Emma
Reimann, Jan
Logic
03F60 (Primary) 28A78 (Secondary)
By reformulating the classical proof as a Baire Category argument, we show that Besicovitch's Theorem in Cantor space is provable in $ACA_0$, and additionally that the witnessing subset is computable from one jump of the original set. We show that the necessary formulation of Baire Category, which we call Baire Category Theorem for Closed Sets (BCTC), is equivalent to $ACA_0$, contrasting with previous results on the reverse math strength of Baire Category variants. We also examine the implications of BCTC for more general monotone functions on closed sets, and explore how changing the representation of a closed set affects the reverse math strength of its measure regularity properties.
title A Baire Category Approach to Besicovitch's Theorem and Measure Regularity
topic Logic
03F60 (Primary) 28A78 (Secondary)
url https://arxiv.org/abs/2602.00940