Locales as spaces in outer models
Abstract
Let M be a transitive model of set theory and X be a space in the sense of M. Is there a reasonable way to interpret X as a space in V? A general theory due to Zapletal provides a natural candidate which behaves well on sufficiently complete spaces (for instance \v{C}ech complete spaces) but behaves poorly on more general spaces - for instance, the Zapletal interpretation does not commute with products. We extend Zapletal's framework to instead interpret locales, a generalization of topological spaces which focuses on the structure of open sets. Our extension has a number of desirable properties; for instance, localic products always interpret as spatial products. We show that a number of localic notions coincide exactly with properties of their interpretations; for instance, we show a locale is if and only if all its interpretations are , a locale is -Hausdorff if and only if all its interpretations are , a locale is regular if and only if all its interpretations are , and a locale is compact if and only if all its interpretations are compact.
Cite
@article{arxiv.2411.05967,
title = {Locales as spaces in outer models},
author = {Nathaniel Bannister},
journal= {arXiv preprint arXiv:2411.05967},
year = {2024}
}