Unbounded towers and products
Abstract
We investigate products of sets of reals with combinatorial covering properties. A topological space satisfies if for each sequence of point-cofinite open covers of the space, one can pick one element from each cover and obtain a point-cofinite cover of the space. We prove that, if there is an unbounded tower, then there is a nontrivial set of reals satisfying in all finite powers. In contrast to earlier results, our proof does not require any additional set-theoretic assumptions. A topological space satisfies (also known as Gerlits--Nagy's property ) if every open cover of the space such that each finite subset of the space is contained in a member of the cover, contains a point-cofinite cover of the space. We investigate products of sets satisfying and their relations to other classic combinatorial covering properties. We show that finite products of sets with a certain combinatorial structure satisfy and give necessary and sufficient conditions when these sets are productively .
Cite
@article{arxiv.1912.02528,
title = {Unbounded towers and products},
author = {Piotr Szewczak and Magdalena Włudecka},
journal= {arXiv preprint arXiv:1912.02528},
year = {2019}
}
Comments
19 pages