{ "id": "2406.11120", "version": "v1", "published": "2024-06-17T00:43:02.000Z", "updated": "2024-06-17T00:43:02.000Z", "title": "Neumann cut-offs and essential self-adjointness on complete Riemannian manifolds with boundary", "authors": [ "Davide Bianchi", "Batu Güneysu", "Alberto G. Setti" ], "categories": [ "math.DG" ], "abstract": "We generalize some fundamental results for noncompact Riemannian manfolds without boundary, that only require completeness and no curvature assumptions, to manifolds with boundary: let $M$ be a smooth Riemannian manifold with boundary $\\partial M$ and let $\\hat{C}^\\infty_c(M)$ denote the space of smooth compactly supported cut-off functions with vanishing normal derivative, Neumann cut-offs. We show, among other things, that under completeness: - $\\hat{C}^\\infty_c(M)$ is dense in $W^{1,p}(\\mathring{M})$ for all $p\\in (1,\\infty)$; this generalizes a classical result by Aubin [2] for $\\partial M=\\emptyset$. - $M$ admits a sequence of first order cut-off functions in $\\hat{C}^\\infty_c(M)$; for $\\partial M=\\emptyset$ this result can be traced back to Gaffney [7]. - the Laplace-Beltrami operator with domain of definition $\\hat{C}^\\infty_c(M)$ is essentially self-adjoint; this is a generalization of a classical result by Strichartz [20] for $\\partial M=\\emptyset$.", "revisions": [ { "version": "v1", "updated": "2024-06-17T00:43:02.000Z" } ], "analyses": { "subjects": [ "58J05", "58J50", "35J25" ], "keywords": [ "complete riemannian manifolds", "neumann cut-offs", "essential self-adjointness", "compactly supported cut-off functions", "first order cut-off functions" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }