{ "id": "1811.03586", "version": "v1", "published": "2018-11-08T18:14:29.000Z", "updated": "2018-11-08T18:14:29.000Z", "title": "A version of Putinar's Positivstellensatz for cylinders", "authors": [ "Paula Escorcielo", "Daniel Perrucci" ], "categories": [ "math.AG" ], "abstract": "We prove that, under some additional assumption, Putinar's Positivstellensatz holds on cylinders of type $S \\times {\\mathbb R}$ with $S = \\{x \\in {\\mathbb R}^n | g_1(x) \\ge 0, ..., g_s(x) \\ge 0\\}$ such that the quadratic module generated by $g_1, ..., g_s$ in ${\\mathbb R}[X_1, ..., X_n]$ is archimedean, and we provide a degree bound for the representation of a polynomial $f \\in {\\mathbb R}[X_1, ..., X_n, Y]$ which is positive on $S \\times {\\mathbb R}$ as an explicit element of the quadratic module generated by $g_1, ..., g_s$ in ${\\mathbb R}[X_1, ..., X_n, Y]$. We also include an example to show that an additional assumption is necessary for Putinar's Positivstellensatz to hold on cylinders of this type.", "revisions": [ { "version": "v1", "updated": "2018-11-08T18:14:29.000Z" } ], "analyses": { "subjects": [ "12D15", "13J30", "14P10" ], "keywords": [ "additional assumption", "quadratic module", "putinars positivstellensatz holds", "explicit element", "degree bound" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }