Seminar series
Date
Fri, 01 Jun 2007
15:15
15:15
Location
L3
Speaker
David Marker
Organisation
University of Illinois, Chicago
Countable Borel equivalence relations arise naturally as orbit equivalence
relations for countable groups. For each countable Borel equivalence relation E
there is an infinitary sentence such that E is equivalent to the isomorphism
relation on countable models of that sentence. For first order theories the
question is open.