3 papers
math.LO2025
A non-computable c.e. closed subset of
Serikzhan Badaev, Nikolay Bazhenov, Sergey Goncharov +2
We prove that there exists a closed subset of that is not homeomorphic to any computably compact space. We show that the index set of c.e. subspaces of that…
math.GR2024
Computably locally compact groups and their closed subgroups
Alexander G. Melnikov, Andre Nies
Given a computably locally compact Polish space , we show that its 1-point compactification is computably compact. Then, for a computably locally compact group , we sho…
math.LO2024
Computable Gelfand Duality
Peter Burton, Christopher J. Eagle, Alec Fox +5
We establish a computable version of Gelfand Duality. Under this computable duality, computably compact presentations of metrizable spaces uniformly effectively correspond to compu…