English

On the torsion function for simply connected, open sets in $\R^2$

Spectral Theory 2024-11-15 v2 Analysis of PDEs

Abstract

For an open set \OmR2\Om \subset \R^2 let λ(\Om)\lambda(\Om) denote the bottom of the spectrum of the Dirichlet Laplacian acting in L2(\Om)L^2(\Om). Let w\Omw_\Om be the torsion function for \Om\Om, and let .p\|.\|_p denote the LpL^p norm. It is shown that there exist {η1>0,η2>0\eta_1>0,\eta_2>0} such that { (i) w\Omλ(\Om)1+η1\|w_{\Om}\|_{\infty} \lambda(\Om)\ge 1+\eta_1 for any non-empty, open, simply connected set \OmR2\Om\subset \R^2 with \lb(\Om)>0\lb(\Om) >0, (ii) w\Om1λ(\Om)(1η2)\Om\|w_{\Om}\|_1\lambda(\Om)\le {(1-\eta_2)}|\Om| for any non-empty, open, simply connected set \OmR2\Om\subset\R^2 with finite measure \Om|\Om|.

Keywords

Cite

@article{arxiv.2402.14448,
  title  = {On the torsion function for simply connected, open sets in $\R^2$},
  author = {Michiel van den Berg and Dorin Bucur},
  journal= {arXiv preprint arXiv:2402.14448},
  year   = {2024}
}

Comments

19 pages, 2 figures

R2 v1 2026-06-28T14:56:55.870Z