DEPARTMENT COLLOQUIUM
November 13, 2002

  Craig Evans
University of California at Berkeley

PDE theory provides weak solutions of certain nonlinear first-order equations which, formally at least, induce simplifying changes of variables for Hamiltonian dynamics. I will discuss an ongoing program to make some part of this observation rigorous, and will in particular explain connections with Mather's variational principle for Lagrangian dynamics and Fathi's ``weak KAM'' theory.