{ "id": "math/0703084", "version": "v2", "published": "2007-03-03T12:14:34.000Z", "updated": "2008-11-11T03:42:27.000Z", "title": "Inequalities and monotonicity of ratios for generalized hypergeometric function", "authors": [ "D. Karp", "S. M. Sitnik" ], "comment": "15 pages, this is the form accepted by Journal of Approximation Theory. Many typos corrected, important references added, several remarks added thoughout the paper. Principal results did not change", "categories": [ "math.CA" ], "abstract": "We find two-sided inequalities for the generalized hypergeometric function of the form ${_{q+1}}F_{q}(-x)$ with positive parameters restricted by certain additional conditions. Both lower and upper bounds agree with the value of ${_{q+1}}F_{q}(-x)$ at the endpoints of positive semi-axis and are asymptotically precise at one of the endpoints. The inequalities are derived from a theorem asserting the monotony of the quotient of two generalized hypergeometric functions with shifted parameters. The proofs hinge on a generalized Stieltjes representation of the generalized hypergeometric function. This representation also provides yet another method to deduce the second Thomae relation for ${_{3}F_{2}}(1)$ and leads to an integral representations of ${_{4}F_{3}}(x)$ in terms of the Appell function $F_3$. In the last section of the paper we list some open questions and conjectures.", "revisions": [ { "version": "v2", "updated": "2008-11-11T03:42:27.000Z" } ], "analyses": { "subjects": [ "33C20" ], "keywords": [ "generalized hypergeometric function", "inequalities", "monotonicity", "upper bounds agree", "second thomae relation" ], "note": { "typesetting": "TeX", "pages": 15, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2007math......3084K" } } }