{ "id": "1506.00025", "version": "v1", "published": "2015-05-29T20:47:53.000Z", "updated": "2015-05-29T20:47:53.000Z", "title": "The Dubovitskiĭ-Sard Theorem in Sobolev Spaces", "authors": [ "Piotr Hajłasz", "Scott Zimmerman" ], "categories": [ "math.CA" ], "abstract": "The Sard theorem from 1942 requires that a mapping $f:\\mathbb{R}^n \\to \\mathbb{R}^m$ is of class $C^k$, $k > \\max (n-m,0)$. In 1957 Duvovitski\\u{\\i} generalized Sard's theorem to the case of $C^k$ mappings for all $k$. Namely he proved that, for almost all $y\\in \\mathbb{R}^m$, $\\mathcal{H}^{\\ell}(C_f \\cap f^{-1}(y))=0$ where $\\ell = \\max(n-m-k+1,0)$, ${\\mathcal H}^{\\ell}$ denotes the Hausdorff measure, and $C_f$ is the set of critical points of $f$. In 2001 De Pascale proved that the Sard theorem holds true for Sobolev mappings of the class $W_{\\rm loc}^{k,p}(\\mathbb{R}^n,\\mathbb{R}^m)$, $k>\\max(n-m,0)$ and $p>n$. We will show that also Dubovitski\\u{\\i}'s theorem can be generalized to the case of $W_{\\rm loc}^{k,p}(\\mathbb{R}^n,\\mathbb{R}^m)$ mappings for all $k\\in\\mathbb{N}$ and $p>n$.", "revisions": [ { "version": "v1", "updated": "2015-05-29T20:47:53.000Z" } ], "analyses": { "subjects": [ "46E35", "58C25" ], "keywords": [ "sobolev spaces", "dubovitskiĭ-sard theorem", "sard theorem holds true", "generalized sards theorem", "sobolev mappings" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }