# Bill Chen: Tight stationarity and pcf theory – part 2

BGU Seminar in Logic, Set Theory and Topology.

Tomorrow we will resume our seminar in Logic, Set Theory and Topology.

Time: Tuesday, November 15, 12:30-13:45.

Place: Seminar room -101, Math building 58.

Speaker: Bill Chen (BGU).

Title: Tight stationarity and pcf theory – part 2

Abstract:
I will introduce the definitions of mutual and tight stationarity due to Foreman and Magidor. These notions generalize the property of stationarity from subsets of a regular cardinal to sequences of subsets of different regular cardinals (or, by some interpretations, to singular cardinals). Tight stationarity will then be related to pcf theory, and from a certain pcf-theoretic assumption we will define a ccc forcing which arranges a particularly nice structure in the tightly stationary sequences.