2009/12/22 by Axel Gruenrock, Gruenrock, Axel
Engineering · Mathematics · Physics and Astronomy · #Advanced Mathematical Physics Problems #Nonlinear Waves and Solitons #Stability and Controllability of Differential Equations #math.AP #msc:35L70
paper · pdf · doi:10.48550/arxiv.0912.4400
arxiv created 2009/12/22 · arxiv updated 2010/01/14
The Cauchy problem for the nonlinear wave equation \Box u=(∂ u)2, u(0)=u0, ut(0)=u1 in three space dimensions is considered. The data (u0,u1) are assumed to belong to \widehatHrs(\R3) × \widehatHrs-1(\R3), where \widehatHrs is defined by the norm \nf\widehatHrs := \n< ξ> s\widehatfLr'ξ, < ξ>=(1+|ξ|2)\frac12, (1)/(r)+(1)/(r')=1. Local well-posedness is shown in the parameter range 2 ≥ r >1, s > 1 + (2)/(r). For r=2 this coincides with the result of Ponce and Sideris, which is optimal on the Hs-scale by Lindblad's counterexamples, but nonetheless leaves a gap of \frac12 derivative to the scaling prediction. This gap is closed here except for the endpoint case. Corresponding results for \Box u = ∂ u2 are obtained, too.