# Jing Zhang: The forcing proof of the Halpern-Läuchli theorem

Mathematical logic seminar – February 23 2016
Time:     12:30 – 13:30

Room:     Wean Hall 8220

Speaker:         Jing Zhang
Department of Mathematical Sciences
CMU

Title:     The forcing proof of the Halpern-Läuchli theorem

Abstract:

We will discuss Harrington’s conceptually simple proof of the Halpern-Läuchli theorem using the machinery of forcing. Also if time permits, we will also briefly discuss its role in establishing the theorem due to Halpern and Lévy: the Boolean Prime Ideal Theorem does not imply the Axiom of Choice over ZF.