Covering versus partitioning with Polish spaces

preprint2021arXivOpen access

Abstract

Given a completely metrizable space XX, let par(X)\mathfrak{par}(X) denote the smallest possible size of a partition of XX into Polish spaces, and cov(X)\mathfrak{cov}(X) the smallest possible size of a covering of XX with Polish spaces. Observe that cov(X)≤par(X)\mathfrak{cov}(X) \leq \mathfrak{par}(X) for every XX, because every partition of XX is also a covering. We prove it is consistent relative to a huge cardinal that the strict inequality cov(X)<par(X)\mathfrak{cov}(X) < \mathfrak{par}(X) can hold for some completely metrizable space XX. We also prove that using large cardinals is necessary for obtaining this strict inequality, because if cov(X)<par(X)\mathfrak{cov}(X) < \mathfrak{par}(X) for any completely metrizable XX, then 0†0^\dagger exists.

Explore this paper’s authors, topics and related work.

Building this map preview

BZPEER is loading the nearby papers, people, topics and institutions for this page.

Reviews 0

Write a reviewWrite

No reviews yet.

Discussion 0

Add a commentWrite

No comments yet.