Mathematical Conversations

For a formal group law G the group of automorphisms Aut(G) acts on the space of deformations Def(G). The invariants of this action miraculously recover an object of huge interest to algebraic topologists, and this connection led to much progress in homotopy theory. However, this action is still not very deeply understood. I will explain the definitions of the objects involved, state known results and talk about some open problems that lie at the intersection of homotopy theory and number theory.