NTP2 topological structures
Logic
2026-05-20 v1
Abstract
A subset of a topological space is constructible if it is a finite Boolean combination of closed sets. We prove that every NTP expansion of by constructible sets defines only constructible sets, and that definable functions are generically piecewise continuous. The result also holds for all NTP expansions of , and all NTP definably complete expansions of ordered groups. In the latter case, the structure is generically locally o-minimal, has definable choice, and carries a well-behaved notion of naive topological dimension. For NIP uniform topological structures, constructibility of definable sets is preserved in the Shelah expansion. We classify strong expansions of by constructible sets, and obtain results on NTP d-minimal structures.
Cite
@article{arxiv.2604.24522,
title = {NTP2 topological structures},
author = {Pablo Andújar Guerrero},
journal= {arXiv preprint arXiv:2604.24522},
year = {2026}
}