Series: Penn State Logic Seminar

Date: Tuesday, September 17, 2002

Time: 2:30 - 3:45 PM

Place: 312 Boucke Building

Speaker: Stephen G. Simpson, Mathematics, Penn State

Title: A Dual Form of Ramsey's Theorem

Abstract: 

The classical Ramsey's Theorem reads as follows.  Let N be a countably
infinite set.  If we color all k-element subsets of N with finitely
many colors, then there exists an infinite subset of N all of whose
k-element subsets have the same color.  The Dual Ramsey Theorem, due
to Carlson and Simpson, reads as follows. If we color all k-element
partitions of N with finitely many Borel colors, then there exists an
infinite partition of N such that all coarser k-element partitions
have the same color.