A Friedberg enumeration of equivalence structures
Rodney G. Downey, Alexander Melnikov, Keng Meng Ng · Journal of Mathematical Logic · 2017
We solve a problem posed by Goncharov and Knight (Problem 4 in [S. Goncharov and J. Knight, Computable structure and antistructure theorems, Algebra Logika 41(6) (2002) 639–681, 757]). More specifically, we produce an effective Friedberg (i.e. injective) enumeration of computable equivalence structures, up to isomorphism. We also prove that there exists an effective Friedberg enumeration of all isomorphism types of infinite computable equivalence structures.