Convexity of the gamma function with respect to Holder means

被引:0
|
作者
Trif, T [1 ]
机构
[1] Univ Babes Bolyai, Fac Matemat Informat, Cluj Napoca, Romania
关键词
gamma function; digamma function; multiplicatively convex function; geometrically convex function;
D O I
暂无
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
We prove that the gamma function is strictly multiplicatively concave on [0, x(0)] and strictly multiplicatively convex on [x(0), infinity], where x(0) is an element of [0, 1] is the unique solution of the equation psi(x) + xpsi'(x) = 0 and psi : [0, infinity] --> R is the digamma function: psi(x) = (dx)-(d) logGamma(x). Thus we answer to an open question raised by C. P. Niculescu [6, p. 164]. Likewise, we investigate the convexity of Gamma with respect to the Holder means.
引用
收藏
页码:189 / 195
页数:7
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