A Solution to Qi’s Conjecture on a Double Inequality for a Function Involving the Tri- and Tetra-Gamma Functions

Ladislav Matejíčka
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Ladislav Matejíčka: Faculty of Industrial Technologies in Púchov, Trenčín University of Alexander Dubček in Trenčín, I. Krasku 491/30, 02001 Púchov, Slovakia

Mathematics, 2019, vol. 7, issue 11, 1-14

Abstract: In the paper, the author gives a solution to a conjecture on a double inequality for a function involving the tri- and tetra-gamma functions, which was first posed in Remark 6 of the paper “Complete monotonicity of a function involving the tri- and tetragamma functions” (2015) and repeated in the seventh open problem of the paper “On complete monotonicity for several classes of functions related to ratios of gamma functions” (2019).

Keywords: digamma function; trigamma function; double optimal inequality (search for similar items in EconPapers)
JEL-codes: C (search for similar items in EconPapers)
Date: 2019
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