{ "id": "2001.06302", "version": "v1", "published": "2020-01-16T00:18:26.000Z", "updated": "2020-01-16T00:18:26.000Z", "title": "On the closest to zero roots and the second quotients of Taylor coefficients of entire functions from the Laguerre-Pólya I class", "authors": [ "Thu Hien Nguyen", "Anna Vishnyakova" ], "comment": "18 pages. Submitted to Results in Mathematics. Partially supported by the Akhiezer Foundation. arXiv admin note: substantial text overlap with arXiv:1903.09070, arXiv:1912.10035", "categories": [ "math.CV", "math.FA" ], "abstract": "For an entire function $f(z) = \\sum_{k=0}^\\infty a_k z^k, a_k>0,$ we show that if $f$ belongs to the Laguerre-P\\'olya class, and the quotients $q_k := \\frac{a_{k-1}^2}{a_{k-2}a_k}, k=2, 3, \\ldots $ satisfy the condition $q_2 \\leq q_3,$ then $f$ has at least one zero in the segment $[-\\frac{a_1}{a_2},0].$ We also give necessary conditions and sufficient conditions of the existence of such a zero in terms of the quotients $q_k$ for $k=2,3, 4.$", "revisions": [ { "version": "v1", "updated": "2020-01-16T00:18:26.000Z" } ], "analyses": { "subjects": [ "30C15", "30D15", "30D35", "26C10" ], "keywords": [ "entire function", "zero roots", "second quotients", "taylor coefficients", "laguerre-pólya" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable" } } }