Cousin's lemma in second-order arithmetic
Logic
2021-05-10 v1
Abstract
Cousin's lemma is a compactness principle that naturally arises when studying the gauge integral, a generalisation of the Lebesgue integral. We study the axiomatic strength of Cousin's lemma for various classes of functions, using Friedman and Simpson's reverse mathematics in second-order arithmetic. We prove that, over : (i) Cousin's lemma for continuous functions is equivalent to ; (ii) Cousin's lemma for Baire class 1 functions is equivalent to ; (iii) Cousin's lemma for Baire class 2 functions, or for Borel functions, are both equivalent to (modulo some induction).
Cite
@article{arxiv.2105.02975,
title = {Cousin's lemma in second-order arithmetic},
author = {Jordan Mitchell Barrett and Rodney G. Downey and Noam Greenberg},
journal= {arXiv preprint arXiv:2105.02975},
year = {2021}
}
Comments
13 pages, no figures