{ "id": "2004.09782", "version": "v1", "published": "2020-04-21T07:17:42.000Z", "updated": "2020-04-21T07:17:42.000Z", "title": "The diamagnetic inequality for the Dirichlet-to-Neumann operator", "authors": [ ". A. F. M. ter Elst", "El Maati Ouhabaz" ], "categories": [ "math.AP", "math.FA" ], "abstract": "Let $\\Omega$ be a bounded domain in R d with Lipschitz boundary $\\Gamma$. We define the Dirichlet-to-Neumann operator N on L 2 ($\\Gamma$) associated with a second order elliptic operator A = -- d k,j=1 $\\partial$ k (c kl $\\partial$ l) + d k=1 b k $\\partial$ k -- $\\partial$ k (c k $\\times$) + a 0. We prove a criterion for invariance of a closed convex set under the action of the semigroup of N. Roughly speaking, it says that if the semigroup generated by --A, endowed with Neumann boundary conditions, leaves invariant a closed convex set of L 2 ($\\Omega$), then the 'trace' of this convex set is invariant for the semigroup of N. We use this invariance to prove a criterion for the domination of semigroups of two Dirichlet-to-Neumann operators. We apply this criterion to prove the diamagnetic inequality for such operators on L 2 ($\\Gamma$).", "revisions": [ { "version": "v1", "updated": "2020-04-21T07:17:42.000Z" } ], "analyses": { "keywords": [ "dirichlet-to-neumann operator", "diamagnetic inequality", "closed convex set", "second order elliptic operator", "neumann boundary conditions" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }