{ "id": "2405.08000", "version": "v1", "published": "2024-05-06T05:08:16.000Z", "updated": "2024-05-06T05:08:16.000Z", "title": "A characterization of the existence of zeros for operators with Lipschitzian derivative and closed range", "authors": [ "Biagio Ricceri" ], "categories": [ "math.FA" ], "abstract": "Let $H$ be a real Hilbert space and $\\Phi:H\\to H$ be a $C^1$ operator with Lipschitzian derivative and closed range. We prove that $\\Phi^{-1}(0)\\neq \\emptyset$ if and only if, for each $\\epsilon>0$, there exist a convex set $X\\subset H$ and a convex function $\\psi:X\\to {\\bf R}$ such that $\\sup_{x\\in X}(\\|x\\|^2+\\psi(x))-\\inf_{x\\in X}\\|x\\|^2+\\psi(x))<\\epsilon$ and $0\\in \\overline{conv}(\\Phi(X))$.", "revisions": [ { "version": "v1", "updated": "2024-05-06T05:08:16.000Z" } ], "analyses": { "keywords": [ "closed range", "lipschitzian derivative", "characterization", "real hilbert space" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }