Computable Stone spaces. / Bazhenov, Nikolay; Harrison-Trainor, Matthew; Melnikov, Alexander.
In: Annals of Pure and Applied Logic, Vol. 174, No. 9, 103304, 01.10.2023.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Computable Stone spaces
AU - Bazhenov, Nikolay
AU - Harrison-Trainor, Matthew
AU - Melnikov, Alexander
N1 - Melnikov and Harrison-Trainor were partially supported by Rutherford Discovery Fellowship (RDF-VUW1902), Royal Society Te Apārangi.The work of Bazhenov and Melnikov is supported by the Mathematical Center in Akademgorodok under agreement No. 075-15-2022-281 with the Ministry of Science and Higher Education of the Russian Federation.
PY - 2023/10/1
Y1 - 2023/10/1
N2 - 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 X, the Banach space C(X;R) has a computable presentation if, and only if, X is homeomorphic to a computably metrized space. This gives an unexpected positive partial answer to a question recently posed by McNicholl.
AB - 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 X, the Banach space C(X;R) has a computable presentation if, and only if, X is homeomorphic to a computably metrized space. This gives an unexpected positive partial answer to a question recently posed by McNicholl.
UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85163195822&origin=inward&txGid=a754f561df57eb3b8612bacca92b7e77
UR - https://www.mendeley.com/catalogue/a3551d3b-ff7c-39c0-9855-df5aa528bbb9/
U2 - 10.1016/j.apal.2023.103304
DO - 10.1016/j.apal.2023.103304
M3 - Article
VL - 174
JO - Annals of Pure and Applied Logic
JF - Annals of Pure and Applied Logic
SN - 0168-0072
IS - 9
M1 - 103304
ER -
ID: 53978703