English

Computable Stone spaces

Logic 2023-11-08 v2

Abstract

We investigate computable metrizability of Polish spaces up to homeomorphism. In this paper we focus on Stone spaces. We use Stone duality to construct the first known example of a computable topological Polish space not homeomorphic to any computably metrized space. In fact, in our proof we construct a right-c.e. metrized Stone space which is not homeomorphic to any computably metrized space. Then we introduce a new notion of effective categoricity for effectively compact spaces and prove that effectively categorical Stone spaces are exactly the duals of computably categorical Boolean algebras. Finally, we prove that, for a Stone space XX, the Banach space C(X;R)C(X;\mathbb{R}) has a computable presentation if, and only if, XX is homeomorphic to a computably metrized space. This gives an unexpected positive partial answer to a question recently posed by McNicholl.

Keywords

Cite

@article{arxiv.2107.01536,
  title  = {Computable Stone spaces},
  author = {Nikolay Bazhenov and Matthew Harrison-Trainor and Alexander Melnikov},
  journal= {arXiv preprint arXiv:2107.01536},
  year   = {2023}
}

Comments

18 pages