Invitation to the Logic Seminar at the National University of Singapore
Date: Wednesday, 16 October 2013, 17:00 hrs
Room: S17#04-06, Department of Mathematics, NUS
Speaker: Li Wei
Title: TT^1 without Sigma_2 Induction
Abstract: TT^1 says that for any coloring of the binary tree with
finitely many colors, there is a homogeneous perfect subtree.
Classically, TT^1 is proved by Sigma_2 Induction. In this talk, we
will examine TT^1 without Sigma_2 Induction and show that for some
recursive coloring, no homogeneous perfect subtree is below 0″.