Monday, March 12, 2012, from 4 to 5:30pm
East Hall, room 2866
Speaker: Andreas Blass (University of Michigan)
Title: Partition Theorems and Ultrafilters
My long-term goal is to discuss a notion of forcing that produces an ultrafilter on the natural numbers that (1) is not a P-point but (2) has the strongest partition properties that are possible subject to (1). These generic ultrafilters have properties similar to those of a sum of non-isomorphic selective ultrafilters indexed by a selective ultrafilter. Nevertheless, they are not sums. My short-term goal is to define and explain the concepts used here — partition properties, P-points, selective ultrafilters, and sums.