Invitation to the Logic Seminar at the National University of Singapore

Date: Wednesday, 7 October 2015, 17:00 hrs

Room: S17#04-06, Department of Mathematics, NUS

Speaker: Dilip Raghavan

Title: Real games and strategically selective coideals, Part 2.

URL: http://www.comp.nus.edu.sg/~fstephan/logicseminar.html

A classical theorem of Mathias says that the Axiom of Determinacy for

Real games (AD_R) implies that there are no tall selective coideals on

omega. Farah introduced the notion of a semiselective coideal and

proved in ZF that these are precisely those ideals on omega whose

quotient adds a selective ultrafilter. It is unkown whether AD_R

implies the non-existence of tall semiselective coideals. We introduce

the notion of strategically selective coideal, and show that tall

strategically selective coideals do not exist under AD_R. The Axiom of

Choice implies that the notions of semiselective and strategically

selective coideal coincide.

This talk is a continuation of the talk from 16/09/2015 and will

provide more mathematical details and selected proofs.

This is joint work with Paul Larson.