# From Cut Elimination to Pi^1_1-Comprehension

**Date**: Wednesday 21 February 2018, 16:00 – 17:00**Location**: Mathematics Level 8, MALL 1, School of Mathematics**Type**: Logic seminars, Pure Mathematics seminars**Cost**: Free

#### Anton Freund, University of Leeds. Part of the logic seminar series.

In the first half of my talk I will introduce some concepts of ordinal analysis. In the second half I will explain how these concepts can be "lifted" to the domain of reverse mathematics. Specifically, I will present a "type-two well-ordering principle" that is equivalent to Pi^1_1-comprehension.