The Additivity of Polygamma Functions

被引：6
|
作者：
Guo, Bai-Ni [1 ]
Qi, Feng [2 ,3 ]
Luo, Qiu-Ming [4 ]
机构：
[1] Henan Polytech Univ, Sch Math & Informat, Jiaozuo City 454010, Henan Province, Peoples R China
[2] Inner Mongolia Univ Nationalities, Coll Math, Tongliao City 028043, Inner Mongolia, Peoples R China
[3] Tianjin Polytech Univ, Coll Sci, Dept Math, Tianjin 300160, Peoples R China
[4] Chongqing Normal Univ, Dept Math, Chongqing 401331, Peoples R China
来源：
FILOMAT | 2015年 / 29卷 / 05期
关键词：
subadditive function; superadditive function; polygamma function; SUPERADDITIVE PROPERTIES; COMPLETE MONOTONICITY; GAMMA; PROPERTY; DIGAMMA;
D O I：
10.2298/FIL1505063G
中图分类号：
O29 [应用数学];
学科分类号：
070104 ;
摘要：
In the paper, the authors prove that the functions vertical bar psi((i))(e(x))vertical bar for i is an element of N are subadditive on (ln theta(i) , infinity) and superadditive on (-infinity, ln theta(i)), where theta(i) is an element of (0; 1) is the unique root of equation 2 vertical bar psi((i))(theta)vertical bar = vertical bar psi((i))(theta)(2)vertical bar.
引用
收藏
页码：1063 / 1066
页数：4
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