{ "id": "2008.04754", "version": "v1", "published": "2020-08-08T19:42:23.000Z", "updated": "2020-08-08T19:42:23.000Z", "title": "On the entire functions from the Laguerre-Pólya I class having the increasing second quotients of Taylor coefficients", "authors": [ "Thu Hien Nguyen", "Anna Vishnyakova" ], "comment": "16 pages. arXiv admin note: text overlap with arXiv:2001.06302, arXiv:1912.10035, arXiv:1903.09070", "categories": [ "math.CV", "math.FA" ], "abstract": "We prove that if $f(x) = \\sum_{k=0}^\\infty a_k x^k,$ $a_k >0, $ is an entire function such that the sequence $Q := \\left( \\frac{a_k^2}{a_{k-1}a_{k+1}} \\right)_{k=1}^\\infty$ is non-decreasing and $\\frac{a_1^2}{a_{0}a_{2}} \\geq 2\\sqrt[3]{2},$ then all but a finite number of zeros of $f$ are real and simple. We also present a criterion in terms of the closest to zero roots for such a function to have only real zeros (in other words, for belonging to the Laguerre--P\\'olya class of type I) under additional assumption on the sequence $Q.$", "revisions": [ { "version": "v1", "updated": "2020-08-08T19:42:23.000Z" } ], "analyses": { "subjects": [ "30C15", "30D15", "30D35", "26C10" ], "keywords": [ "increasing second quotients", "entire function", "taylor coefficients", "laguerre-pólya", "finite number" ], "note": { "typesetting": "TeX", "pages": 16, "language": "en", "license": "arXiv", "status": "editable" } } }