{ "id": "1305.2137", "version": "v1", "published": "2013-05-09T16:25:19.000Z", "updated": "2013-05-09T16:25:19.000Z", "title": "On the torsion function with Robin or Dirichlet boundary conditions", "authors": [ "M. van den Berg", "D. Bucur" ], "comment": "19 pages", "categories": [ "math.AP" ], "abstract": "For $p\\in (1,+\\infty)$ and $b \\in (0, +\\infty]$ the $p$-torsion function with Robin boundary conditions associated to an arbitrary open set $\\Om \\subset \\R^m$ satisfies formally the equation $-\\Delta_p =1$ in $\\Om$ and $|\\nabla u|^{p-2} \\frac{\\partial u}{\\partial n} + b|u|^{p-2} u =0$ on $\\partial \\Om$. We obtain bounds of the $L^\\infty$ norm of $u$ {\\it only} in terms of the bottom of the spectrum (of the Robin $p$-Laplacian), $b$ and the dimension of the space in the following two extremal cases: the linear framework (corresponding to $p=2$) and arbitrary $b>0$, and the non-linear framework (corresponding to arbitrary $p>1$) and Dirichlet boundary conditions ($b=+\\infty$). In the general case, $p\\not=2, p \\in (1, +\\infty)$ and $b>0$ our bounds involve also the Lebesgue measure of $\\Om$.", "revisions": [ { "version": "v1", "updated": "2013-05-09T16:25:19.000Z" } ], "analyses": { "subjects": [ "35J25", "35P99", "58J35" ], "keywords": [ "dirichlet boundary conditions", "torsion function", "arbitrary open set", "extremal cases", "robin boundary conditions" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1305.2137V" } } }