Speaker:
Geoff Galgon
Institution:
UCI
Time:
Monday, November 24, 2014 - 4:00pm to 5:30pm
Host:
Location:
RH 440R
We introduce the approachability ideal I[\kappa] for regular \kappa, make some basic observations, and establish a connection with internally approachable models. Using the trichotomy theorem to guarantee the existence of an exact upper bound for a certain sequence, we proceed 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.