{ "id": "2204.01045", "version": "v1", "published": "2022-04-03T10:56:18.000Z", "updated": "2022-04-03T10:56:18.000Z", "title": "When does a hypergeometric function ${}_{p\\!}F_q$ belong to the Laguerre--Pólya class $LP^+$?", "authors": [ "Alan D. Sokal" ], "comment": "10 pages, LaTeX2e", "categories": [ "math.CA", "math.CV" ], "abstract": "I show that a hypergeometric function ${}_{p}F_q(a_1,\\ldots,a_p;b_1,\\ldots,b_q;\\,\\cdot\\,)$ with $p \\le q$ belongs to the Laguerre--P\\'olya class $LP^+$ for arbitrarily large $b_{p+1},\\ldots,b_q > 0$ if and only if, after a possible reordering, the differences $a_i - b_i$ are nonnegative integers. This result arises as an easy corollary of the case $p=q$ proven two decades ago by Ki and Kim. I also give explicit examples for the case ${}_{1}F_2$.", "revisions": [ { "version": "v1", "updated": "2022-04-03T10:56:18.000Z" } ], "analyses": { "subjects": [ "33C20", "30B70", "30C15", "30D20", "30E05", "44A60" ], "keywords": [ "hypergeometric function", "laguerre-pólya class", "laguerre-polya class", "result arises", "explicit examples" ], "note": { "typesetting": "LaTeX", "pages": 10, "language": "en", "license": "arXiv", "status": "editable" } } }