A priori estimates for the derivative nonlinear Schrödinger equation
arXiv:2007.13161 · doi:10.1619/fesi.65.329
Abstract
We prove low regularity a priori estimates for the derivative nonlinear Schrödinger equation in Besov spaces with positive regularity index conditional upon small -norm. This covers the full subcritical range. We use the power series expansion of the perturbation determinant introduced by Killip--Vişan--Zhang for completely integrable PDE. This makes it possible to derive low regularity conservation laws from the perturbation determinant.
14 pages, revised version, to appear in Funkcial. Ekvac