English

On a Theorem of Wolff Revisited

Analysis of PDEs 2020-02-13 v1 Classical Analysis and ODEs

Abstract

We study pp-harmonic functions, 1<p2< 1 < p\neq 2 < \infty, in R+2={z=x+iy:y>0,<x<} \mathbb{R}^{2}_+ = \{ z = x + i y : y > 0, - \infty < x < \infty \} and B(0,1)={z:z<1}B( 0, 1 ) = \{ z : |z| < 1 \}. We first show for fixed p p, 1<p2<1 < p\neq 2 < \infty, and for all large integers NN0N\geq N_0 that there exists pp-harmonic function, V=V(reiθ) V = V ( r e^{i\theta} ), which is 2π/N 2\pi/N periodic in the θ \theta variable, and Lipschitz continuous on B(0,1) \partial B (0, 1) with Lipschitz norm cN\leq c N on B(0,1) \partial B ( 0, 1 ) satisfying V(0)=0V(0)=0 and c1ππV(eiθ)dθc c^{-1} \leq \int_{-\pi}^{\pi} V ( e^{i\theta} ) d \theta \leq c. In case 2<p<2<p<\infty we give a more or less explicit example of VV and our work is an extension of a result of Wolff on R+2 \mathbb{R}^{2}_+ to B(0,1) B (0, 1). Using our first result, we extend the work of Wolff on failure of Fatou type theorems for R+2 \mathbb{R}^{2}_+ to B(0,1) B (0, 1) for pp-harmonic functions, 1<p2<1< p\neq 2<\infty. Finally, we also outline the modifications needed for extending the work of Llorente, Manfredi, and Wu regarding failure of subadditivity of pp-harmonic measure on R+2 \partial \mathbb{R}^{2}_+ to B(0,1)\partial B (0, 1).

Keywords

Cite

@article{arxiv.2002.04677,
  title  = {On a Theorem of Wolff Revisited},
  author = {Murat Akman and John Lewis and Andrew Vogel},
  journal= {arXiv preprint arXiv:2002.04677},
  year   = {2020}
}

Comments

38 pages, 1 figure

R2 v1 2026-06-23T13:38:53.706Z