# From Hilbert's programme to ordinal analysis.

Michael Rathjen University of Leeds 4pm Tuesday 13th November 2007 Room 2511, JCMB, King's Buildings

Ordinal analysis of theories is a core area of proof theory. The origins of proof theory can be traced back to the second problem on Hilbert's famous list of problems. Proof theory was invented as the main tool for carrying out Hilbert's programme. In the main, ordinal-theoretic proof theory came into existence in 1936, springing forth from Gentzen's consistency proof of arithmetic. The intent of the talk is to elucidate the underlying notions and the rationale of ordinal-theoretic proof theory by relating the developments from Gentzen up to recent advances in ordinal analysis of strong theories.