Mathematical logic seminar - Nov 9, 2010

Time: 12:00 - 13:20

Room: Wean Hall 7201

Speaker:     Spencer Unger    
Department of Mathematical Sciences
Carnegie Mellon University

Title: Recent work on the tree property III


This week I will focus on the following theorem. Let M be Mitchell's partial ordering from the previous two talks. Working in V^M, let Q be either ccc forcing of size aleph1 or Add(omega,mu) for some infinite mu. Then the tree property holds at omega2 in V^{M*Q}. The theorem is essentially an application of a new branch lemma. In this talk, I will sketch a proof of both the theorem and the lemma.