# James Cummings: Some strong chain conditions

Mathematical logic seminar – Feb 20 2018
Time:     3:30pm – 4:30 pm

Room:     Wean Hall 8220

Speaker:         James Cummings
Department of Mathematical Sciences
CMU

Title:     Some strong chain conditions

Abstract:

One of the basic facts in forcing is that a finite support iteration of ccc forcing is ccc. This underlies (for example) the consistency proof for Martin’s Axiom. In general an iteration of κ-closed κ+-cc forcing with <κ-support fails to be κ+-cc, and we need strngthened forms of the chain condition. I will discuss some of these strong chain conditions and the corresponding iteration theorems.