An effective version of the Stone duality
Abstract
The paper studies computability-theoretic aspects of topological -spaces. We introduce effective versions of the notions of a countable -poset and a (second-countable) topological space with base. Based on this, we prove an effective version of the known Stone-type duality between the category (whose objects are almost semispectral spaces with base and whose morphisms are spectral mappings) and the category (whose objects are distributive -posets and whose morphisms are strict mappings). Namely, we show that for an arbitrary set , this duality is preserved when one restricts to objects which have -computably enumerable presentations only. Following this approach, we establish several results in computable topology. We prove that every degree spectrum of a countable algebraic structure can be realized as the degree spectrum of a topological space with base. We show that for any non-zero natural number , there is a computable topological space with base that has precisely -many computable copies, up to effective spectral homeomorphisms.
Keywords
Cite
@article{arxiv.2604.04492,
title = {An effective version of the Stone duality},
author = {Nikolay A. Bazhenov and Iskander Sh. Kalimullin and Marina V. Schwidefsky},
journal= {arXiv preprint arXiv:2604.04492},
year = {2026}
}
Comments
18 pages