English

Almost Everywhere Regularity for the Free Boundary of the Normalized p-harmonic Obstacle problem $p>2$

Analysis of PDEs 2016-11-15 v1

Abstract

Let uu be a solution to the normalized p-harmonic obstacle problem with p>2p>2. That is, uW1,p(B1(0))u\in W^{1,p}(B_1(0)), 2<p<2<p<\infty, u0u\ge 0 and \d(up2u)=χ{u>0} in B1(0) \d\left( |\nabla u|^{p-2}\nabla u\right)=\chi_{\{u>0\}}\textrm{ in }B_1(0) where u(x)0u(x)\ge 0 and χA\chi_A is the characteristic function of the set AA. Our main result is that for almost every free boundary point, with respect to the (n1)(n-1)-Hausdorff measure, there is a neighborhood where the free boundary is a C1,βC^{1,\beta}-graph. That is, for \H^{n-1}-a.e. point x0{u>0}B1(0)x^0\in \partial \{u>0\}\cap B_1(0) there is an r>0r>0 such that Br(x0){u>0}C1,βB_r(x^0)\cap \partial \{u>0\}\in C^{1,\beta}.

Keywords

Cite

@article{arxiv.1611.04397,
  title  = {Almost Everywhere Regularity for the Free Boundary of the Normalized p-harmonic Obstacle problem $p>2$},
  author = {John Andersson},
  journal= {arXiv preprint arXiv:1611.04397},
  year   = {2016}
}