Monday, October 21, 2013, 16.30
Seminar room 1.008, Mathematical Institute, University of Bonn
Speaker: Ralf Schindler (University of Münster)
Title: Does Pi-1-1 determinacy yield 0#?
Abstract: It is unknown whether Pi-1-1 determinacy yields 0# in third order arithmetic. We show that third order arithmetic plus Harrington’s principle “there is a real x such that every x-admissible is an L-cardinal” is equiconsistent with ZFC plus a remarkable cardinal, and we also discuss strengthenings of Harrington’s principle. This is joint work with Cheng Yong.