Effective cardinals in the nonstandard universe

Research paper by Vladimir Kanovei, Michael Reeken

Indexed on: 02 Dec '05Published on: 02 Dec '05Published in: Mathematics - Logic


We study the structure of effective cardinals in the nonstandard set universe of Hrbacek set theory HST. Some results resemble those known in descriptive set theory in the domain of Borel reducibility of equivalence relations.