2011/03/22 by Burak Erdogan, Erdogan, Burak, Nikolaos Tzirakis +1 · 4 citations
Mathematics · #35q53 #Analysis of PDEs (math.AP) #FOS: Mathematics #math.AP #msc:35q53
paper · pdf · doi:10.48550/arxiv.1103.4190
24 pages. We demonstrate smoothing for both KdV and mKdV
arxiv created 2011/03/29 · arxiv updated 2011/03/30
The Korteweg-de Vries (KdV) equation with periodic boundary conditions is considered. It is shown that for Hs initial data, s>-1/2, and for any s1<min(3s+1,s+1), the difference of the nonlinear and linear evolutions is in Hs1 for all times, with at most polynomially growing Hs1 norm. The result also extends to KdV with a smooth, mean zero, time-dependent potential in the case s≥ 0. Our result and a theorem of Oskolkov for the Airy evolution imply that if one starts with continuous and bounded variation initial data then the solution of KdV (given by the L2 theory of Bourgain) is a continuous function of space and time. In addition, we demonstrate smoothing for the modified KdV equation on the torus for s>1/2.