2000/05/31 by Terence Tao · 5 citations
Mathematics · #math.AP #msc:35G25 #msc:42B35 #msc:35L70 #msc:35Q53 #msc:35Q55
published as Amer. J. Math. 123 (2001), 839-908 · 50 pages. An incorrect estimate has been fixed
arxiv created 2004/03/04 · arxiv updated 2009/11/30
The Xs,b spaces, as used by Beals, Bourgain, Kenig-Ponce-Vega, Klainerman-Machedon and others, are fundamental tools to study the low-regularity behaviour of non-linear dispersive equations. It is of particular interest to obtain bilinear or multilinear estimates involving these spaces. By Plancherel's theorem and duality, these estimates reduce to estimating a weighted convolution integral in terms of the L2 norms of the component functions. In this paper we systematically study weighted convolution estimates on L2. As a consequence we obtain sharp bilinear estimates for the KdV, wave, and Schrödinger Xs,b spaces.