3 papers
math.LO2020
A Note on Computable Embeddings for Ordinals and Their Reverses
Nikolay Bazhenov, Stefan Vatev
We continue the study of computable embeddings for pairs of structures, i.e. for classes containing precisely two non-isomorphic structures. Surprisingly, even for some pairs of si…
math.LO2019
Minimal Equivalence Relations in Hyperarithmetical and Analytical Hierarchies
Nikolay Bazhenov, Manat Mustafa, Luca San Mauro +1
A standard tool for classifying the complexity of equivalence relations on is provided by computable reducibility. This reducibility gives rise to a rich degree structure. The…
math.LO2018
Classifying equivalence relations in the Ershov hierarchy
Nikolay Bazhenov, Manat Mustafa, Luca San Mauro +2
Computably enumerable equivalence relations (ceers) received a lot of attention in the literature. The standard tool to classify ceers is provided by the computable reducibility $\…