A Kuratowski closure-complement variant whose solution is independent of ZF
General Topology
2020-05-28 v1
Abstract
We pose the following new variant of the Kuratowski closure-complement problem: How many distinct sets may be obtained by starting with a set of a Polish space , and applying only closure, complementation, and the operator, as often as desired, in any order? The set operator was studied by Kuratowski in his foundational text \textit{Topology: Volume I}; it assigns to the collection of all points of second category for . We show that in ZFC set theory, the answer to this variant problem is . In a distinct system equiconsistent with ZFC, namely ZF+DC+PB, the answer is only .
Cite
@article{arxiv.2005.13009,
title = {A Kuratowski closure-complement variant whose solution is independent of ZF},
author = {Michael P. Cohen and Todd Johnson and Adam Kral and Aaron Li and Justin Soll},
journal= {arXiv preprint arXiv:2005.13009},
year = {2020}
}
Comments
9 pages, 3 figures