From Stationary Phase to Steepest Descent
Abstract
Description
Our aim here is to clarify the distinction between the nonlinear-stationary-phase idea and the nonlinear-steepest-descent idea, stressing the importance of actual steepest-descent contours in some problems. We mostly use the nonlinear Schrödinger equation as our working model, but we also digress to the KdV equation at some point.
This is a slightly revised version of a review paper that will appear in the forthcoming volume (Contemporary Mathematics, AMS) honoring Percy Deift.
Dedicated to Percy Deift on his 60th birthday
Dedicated to Percy Deift on his 60th birthday