Todorcevic's proof of Baumgartner Axiom

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Speaker: 
Garrett Ervin
Institution: 
UCI
Time: 
Mon, 10/20/2014 - 4:00pm - 5:30pm
Host: 
Martin Zeman
Location: 
RH 440R

Baumgartner's Axiom postulates that any two $\aleph_1$-dense subsets of the real line are order-isomorphic. A set is $\aleph_1$-dense iff every nonempty open interval intersects the set in $\aleph_1$-many points. We present Todorcevic's argument which shows that Baumgartner's Axiom is a consequence of the Proper Forcing Axiom.