Logic Seminar
Jay Williams
Rutgers University
Group embeddability and countable Borel quasi-orders
Abstract: Descriptive set theory gives us a framework for analyzing the
relative complexity of quasi-orders (i.e. reflexive transitive relations)
arising in many areas of mathematics, such as Turing reducibility of sets of
natural numbers or embeddability of countable groups, using the notion of a
Borel reduction. I will discuss a special class of quasi-orders, the
countable Borel quasi-orders, and focus in particular on embeddability of
finitely-generated groups, answering a question of Louveau and Rosendal.
The ideas in this case will apply to the more general case of embeddability
of countable groups.
Thursday October 27, 2011 at 3:00 PM in SEO 1227