Piotr Przytycki, McGill University

A CAT(0) space for the 3-dimensional tame automorphism group.

The 3-dimensional tame automorphism group Tame(k^3) is the group of automorphisms of k^3 generated by affine maps and maps of form (x,y,z)→(x+P(y,z),y,z) for P a polynomial in k[y,z]. We construct a simply-connected non-positively curved space with an action of Tame(k^3). That leads to the classification of finite subgroups of Tame(k^3). This is joint work with Stéphane Lamy.