The CMU mathematical logic seminar will meet Tue 22 Oct
12:00-1:30 in Wean Hall 7201.
Alexei Kolesnikov will continue his talk from last Tuesday.
Note to newcomers: Seminar follows a “brown bag lunch” format and for
the first ten minutes or so we chat and have lunch. The actual
talk usually runs 12:10-1:20 or so.
Alexei Kolesnikov (Towson University)
Generalized Martin’s axiom and disjoint amalgamation.
In a joint work with Baldwin and Shelah, we construct examples of abstract
elementary classes that have the disjoint amalgamation property for models of size up to $\beth_\alpha$, but ultimately failing to have the disjoint amalgamation for sufficiently large models. The argument relies on a set-theoretic principle introduced by Shelah. A form of that principle was used by Shelah to study simple unstable theories.