Countable models and the theory of Borel equivalence relations Greg Hjorth

Possibility (ii) from Silver’s theorem represents the start of a very long story. The first major result was obtained at the end of the 1980s:

(i) (ii)

It takes a nontrivial amount of descriptive set theory to prove this theorem. Instead I will probably try to work through the analogue for isomorphism relation on countable structures.