{ "id": "1602.04618", "version": "v1", "published": "2016-02-15T10:46:05.000Z", "updated": "2016-02-15T10:46:05.000Z", "title": "On Polya's inequality for torsional rigidity and first Dirichlet eigenvalue", "authors": [ "M. van den Berg", "V. Ferone", "C. Nitsch", "C. Trombetti" ], "comment": "18 pages", "categories": [ "math.AP" ], "abstract": "Let $\\Omega$ be an open set in Euclidean space with finite Lebesgue measure $|\\Omega|$. We obtain some properties of the set function $F:\\Omega\\mapsto \\R^+$ defined by $$ F(\\Omega)=\\frac{T(\\Omega)\\lambda_1(\\Omega)}{|\\Omega|} ,$$ where $T(\\Omega)$ and $\\lambda_1(\\Omega)$ are the torsional rigidity and first eigenvalue of the Dirichlet Laplacian respectively. We improve the classical P\\'olya bound $F(\\Omega)\\le 1,$ and show that $$F(\\Omega)\\le 1- \\nu_m T(\\Omega)|\\Omega|^{-1-\\frac2m},$$ where $\\nu_m$ depends on $m$ only. For any $\\epsilon\\in (0,1)$ we construct an open set $\\Omega_{\\epsilon}$ such that $F(\\Omega_{\\epsilon})\\ge 1-\\epsilon$.", "revisions": [ { "version": "v1", "updated": "2016-02-15T10:46:05.000Z" } ], "analyses": { "subjects": [ "49J45", "49R05", "35P15", "47A75", "35J25" ], "keywords": [ "first dirichlet eigenvalue", "torsional rigidity", "polyas inequality", "open set", "finite lebesgue measure" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2016arXiv160204618V" } } }