Recent and upcoming talks by David Belanger

David Belanger: An effective perfect-set theorem

Invitation to the Logic Seminar at the National University of Singapore Date: Wednesday, 9 Nov 2016, 17:00 hrs Room: S17#04-05, Department of Mathematics, NUS Speaker: David Belanger Title: An effective perfect-set theorem URL: http://www.comp.nus.edu.sg/~fstephan/logicseminar.html Abstract: We gauge the difficulty of finding a perfect subtree in a tree of a given Cantor-Bendixson rank. continue reading…

David Belanger: New conservation theorems for COH

Invitation to the Logic Seminar at the National University of Singapore Date: Wednesday, 9 September 2015, 17:00 hrs Room: S17#04-06, Department of Mathematics, NUS Speaker: David Belanger Title: New conservation theorems for COH URL: http://www.comp.nus.edu.sg/~fstephan/logicseminar.html We prove a series of conservation results for COH over various axiom systems, extending earlier results of Cholak-Jockusch-Slaman and of Chong-Slaman-Yue. continue reading…