中文

关于调和函数等值线的曲率

经典分析与常微分方程 2014-07-02 v5 偏微分方程分析

摘要

如果开单位圆盘 B(0,1)R2B(0,1) \subset \mathbb{R}^2 内的实调和函数其等值集 {x:u(x)=u(0)}\left\{x: u(x) = u(0)\right\} 微分同胚于一个区间,那么我们证明了该等值集 {x:u(x)=u(0)}\left\{x: u(x) = u(0)\right\} 在原点处的曲率具有尖锐上界 κ8\kappa \leq 8。该界是尖锐的,并且我们给出了唯一的(至多相差对称性)极值函数。

关键词

引用

@article{arxiv.1307.2069,
  title  = {On the curvature of level sets of harmonic functions},
  author = {Stefan Steinerberger},
  journal= {arXiv preprint arXiv:1307.2069},
  year   = {2014}
}

备注

This paper is withdrawn: the result has been proven earlier by Kuran (On the zeros of harmonic functions, J. London Math. Soc. 44, 1969, 303-309)