# James Cummings: Forcing Pi_2 statements II

Mathematical logic seminar – September 22, 2015
Time:     12:30 – 13:30

Room:     Wean Hall 7201

Speaker:         James Cummings
Department of Mathematical Sciences
CMU

Title:     Forcing Pi_2 statements II

Abstract:

We often find ourselves needing to force assertions of the general form “for every x there exists y….” where typically x and y are subsets of some regular cardinal κ

We will consider three general cases (of increasing difficulty)

κ is ω1
κ is the successor of an uncountable regular cardinal
κ is the successor of a singular cardinal