2 papers
math.LO2021
Continuous logic and Borel equivalence relations
Andreas Hallbäck, Maciej Malicki, Todor Tsankov
We study the complexity of isomorphism of classes of metric structures using methods from infinitary continuous logic. For Borel classes of locally compact structures, we prove tha…
math.LO2020
Automorphism groups of universal diversities
Andreas Hallbäck
We prove that the automorphism group of the Urysohn diversity is a universal Polish group. Furthermore we show that the automorphism group of the rational Urysohn diversity has amp…