{ "id": "1812.04874", "version": "v1", "published": "2018-12-12T10:14:40.000Z", "updated": "2018-12-12T10:14:40.000Z", "title": "Exponential convexifying of polynomials", "authors": [ "Krzysztof Kurdyka", "Katarzyna Kuta", "Stanisław Spodzieja" ], "comment": "19 pages", "categories": [ "math.AG", "math.CA" ], "abstract": "Let $X\\subset\\mathbb{R}^n$ be a convex closed and semialgebraic set and let $f$ be a polynomial positive on $X$. We prove that there exists an exponent $N\\geq 1$, such that for any $\\xi\\in\\mathbb{R}^n$ the function $\\varphi_N(x)=e^{N|x-\\xi|^2}f(x)$ is strongly convex on $X$. When $X$ is unbounded we have to assume also that the leading form of $f$ is positive in $\\mathbb{R}^n\\setminus\\{0\\}$. We obtain strong convexity of $\\varPhi_N(x)=e^{e^{N|x|^2}}f(x)$ on possibly unbounded $X$, provided $N$ is sufficiently large, assuming only that $f$ is positive on $X$. We apply these results for searching critical points of polynomials on convex closed semialgebraic sets.", "revisions": [ { "version": "v1", "updated": "2018-12-12T10:14:40.000Z" } ], "analyses": { "subjects": [ "11E25", "12D15", "26B25" ], "keywords": [ "polynomial", "exponential convexifying", "convex closed semialgebraic sets", "strong convexity", "strongly convex" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable" } } }