Geometric renormalization of wave maps
Terence Tao
UCLA
Mathematics
We discuss the global regularity problem for wave maps, and the difficulties in solving this equation arising from divergences in the non-linear part of the flow. We discuss a number of renormalization techniques available to eliminate these divergences: a microlocal renormalization, a Coulomb gauge renormalization, and a more recent geometric renormalization based on the harmonic map heat flow which shows some promise for dealing with the large energy case.