Silver's Dichotomy | Department of Mathematics

Silver's Dichotomy

Event Information
Event Location: 
GAB 461
Event Date: 
Wednesday, April 9, 2014 - 3:30pm

Using a combination of effective descriptive set theory and topological methods, we will prove Silver's theorem that every coanalytic equivalence relation on a standard Borel space has either countably many or perfectly many equivalence classes. By 'perfectly many' we mean that the Cantor set can be continuously embedded into the quotient space, which is stronger than just having continuum many classes.