Sam Ziegler : The $S_{\infty}$-universality of countable graphs

Posted by Sam Ziegler , part of the Louise Hay Logic Seminar.

At

Oct. 18, 2012, 3 p.m.

In

SEO 427

Abstract

In this talk, we prove that the logic action of $S_{\infty}$ on the space of countable graphs is universal, in the sense that any $S_{\infty}$ orbit equivalence relation Borel reduces to the orbit equivalence relation on graphs.