Time:  12:00  13:20 
Room: 
Porter Hall A 19 D

Speaker: 
Henry Towsner Department of Mathematical Sciences Carnegie Mellon University 
Title: 
Interpreting Set Theory with Inductive Definitions

Abstract:  Abstract: The weak set theory KPw is equivalent to the theory ID1 of monotone inductive definitions, however while the former can describe most ordinary mathematics with minimal coding, and the later has a very elegant proof theoretic analysis, for a long time it appeared that the only embedding of KPw in ID1 was the brute force version given by encoding the entire cutelimination proof. I will present a more natural embedding (requiring a minimum of coding and no ordinals) due to Christian Tapp. 