# William Chen: ANTICHAINS, THE STICK PRINCIPLE, AND A MATCHING NUMBER

Place: Fields Institute (Library)
Date:  September 2, 2018 (13:30-15:00)
Speaker: William Chen
Title: ANTICHAINS, THE STICK PRINCIPLE, AND A MATCHING NUMBER
Abstract: This talk is about some cardinal invariants related to $\omega_1$. The
antichain number is the least cardinal for which there does not exist a
subcollection of that size with pairwise finite intersections, and the
matching number is the least cardinal for which there exists a
subcollection X of that size of order-type $\omega$ subsets of $\omega_1$
so that every uncountable subset of $\omega_1$ has infinite intersection
with a member of X. We explore how these invariants behave in various
forcing extensions. Joint work with Geoff Galgon.

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