A new solution to the von Neumann-Day problem for finitely presented groups.

Abstract : In this talk, I will describe a finitely presented subgroup of Monod’s group of piecewise projective homeomorphisms of the real line. This in particular provides a new example of a finitely presented group which is nonamenable and yet does not contain a nonabelian free subgroup. The example is moreover torsion free. A portion of this is joint work with Justin Moore.