Ernest Schimmerling

Mid-Atlantic Mathematical Logic Seminar

Andrés Villaveces (Bogotá and CMU)

On excellent classes

Excellent classes were initially used by Shelah in several classification theory contexts. Later, they have been studied as interesting platforms for extending the classification theory program to non elementary classes (Grossberg, Hart) and they have appeared in several unexpected connections (almost free algebras, Mekler-Shelah) and very recently, as a very natural framework for Zilber's study of the Schanuel Conjecture. I will present two examples that show the necessity of excellence in some contexts of study of spectra functions.