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.LO2014
Independence in computable algebra
Matthew Harrison-Trainor, Alexander Melnikov, Antonio Montalbán
We give a sufficient condition for an algebraic structure to have a computable presentation with a computable basis and a computable presentation with no computable basis. We apply…