Speaker:
Geoff Galgon
Institution:
UCI
Time:
Monday, December 1, 2014 - 4:00pm to 5:30pm
Host:
Location:
RH 440R
Last week we introduced the approachability ideal and internally approachable structures, and made some basic observations. We continue this week using the trichotomy theorem to guarantee the existence of an exact upper bound for a certain sequence, and use this to prove the existence in ZFC of a scale of length \aleph_{\omega+1} in a reduced product \omega_k for k \in A, an infinite subset of \omega.