The best bounds in Wallis' inequality

For all natural numbers , let denote a double factorial. Then

The constants and are the best possible. From this, the well-known Wallis' inequality is improved.

     

Minc H和Sathre L不等式最好的界

给出了函数f(x)和g(x)单调性的证明.据此,得到了著名的Minc H和Sathre L不等式最好的界.     

关于未解决的一个不等式问题的注记(英文)

文[6]中,F.Qi提出了一个未解决的不等式问题.本文给出了此问题的答案和进一步的拓广,同时也得到了该问题的反向不等式.     

Complete monotonicity and logarithmically complete monotonicity properties for the gamma and psi functions

We present some complete monotonicity and logarithmically complete monotonicity properties for the gamma and psi functions. This extends some known results due to S.-L. Qiu and M. Vuorinen.     

关于$\Gamma$函数的一个凸性结果及其应用

利用Γ函数和它的对数微商的一些性质以及Laplace变换的卷积定理,Γ函数的一个凸性结果被获得．作为应用,著名的Wallis不等式被改进．     

Remarks on some completely monotonic functions

Applying the Euler-Maclaurin summation formula, we obtain upper and lower polynomial bounds for the function , x>0, with coefficients the Bernoulli numbers Bk. This enables us to give simpler proofs of some results of H. Alzer and F. Qi et al., concerning complete monotonicity of certain functions involving the gamma function Γ(x), the psi function ψ(x) and the polygamma functions ψ(n)(x), n=1,2,… .     

Remarks on a paper by El-Guindy and Papanikolas

The Ramanujan Journal - There are similarities between Drinfeld modules and abelian varieties. The purpose of this paper is to investigate these similarities in terms of supersingularity. More...     

关于一个积分不等式的一些注记

Given two positive constantsαandβ,we prove that the integral inequality∫_0~1 f~(α+β)(x)dx≥∫_0~1 f~α(x)x~βdx holds for all non-negative valued continuous functions f satisfying∫_x~1 f(t)dt≥∫_x~1 tdt for x∈[0,1]if and only ifα+β≥1.This solves an open problem proposed recently by Ngo,Thang,Dat,and Tuan.     

关于伽玛函数和不完全伽玛函数单调性的注记

利用含有两参数拓广加权平均值的单调性和不等式,我们证明了三类比的伽玛函数在条件r＞0,s＞0和x＞0下是递增的,Γ(s),Γ(s,x)和γ(s,x)分别表示伽玛函数和不完全伽玛函数.据此关于伽玛函数和不完全伽玛函数的单调性结果和不等式被推广了,同时给出了伽玛函数一些结果的证明.     

一类函数的对数完全单调性

通过对参数λ,μ的讨论,主要利用函数的单调性理论,已有对数完全单调函数的性质以及幂函数的积分表达式研究了函数Gλ,μ(x)及函数[Gλ,μ(x)]-1的对数完全单调性,并在此基础上得到了一定条件下函数Gλ,μ(x)及[Gλ,μ(x)]-1对数完全单调的充要条件.     

包含函数Γ（x）的对数完全单调函数及不等式

基于欧拉Gamma函数的奇特性质,利用函数的单调性理论以及一些简单函数的积分表达式与级数展开式证明了函数f_α(x),α∈R和函数s(x)的对数完全单调性,并利用该性质得出了一个比原有结论更精确的不等式以及一个双边不等式.     

Remarks on the Extremal Functions for the Moser-Trudinger Inequality

We will show in this paper that if A is very close to 1, then I（M,λ,m） =supu∈H0^1,n（m）,∫m｜△↓u｜^ndV=1∫Ω（e^αn｜u｜^n/（n-1）-λm∑k=1｜αnun/（n-1）｜k/k!）dV can be attained, where M is a compact-manifold with boundary. This result gives a counter-example to the conjecture of de Figueiredo and Ruf in their paper titled ＂On an inequality by Trudinger and Moser and related elliptic equations＂ （Comm. Pure. Appl. Math., 55, 135-152, 2002）.     

与几何凹函数相关的函数的准线性研究

先介绍四个与几何凹函数定积分有关的不等式,后相应定义了四个函数,证明了它们具有某种准线性.作为应用,由此可得到这些函数的单调性,使得这四个不等式在理论上得到推广和完善,并且部分解决了一个公开问题.     

Estimating the digamma and trigamma functions by completely monotonicity arguments

We establish new sharp bounds for the digamma and trigamma functions, using the complete monotonicity of some class of functions.     

Remarks on a paper of Bachelis and Gilbert

Several formulas for translation-invariant operator ideals overL ^p-spaces of compact groups are proved by tensor product methods.     

Hardy-Hilbert不等式的推广

本文利用权系数方法,给出了一个推广的具有最佳常数因子的Hardy-Hilbert不等式,并考虑了它的一些特殊结果.     

一个基本的Hilbert型积分不等式及推广

利用权函数的方法,建立一个新的、基本的不含参量的Hilbert型积分不等式,并证明其常数因子为最佳值.还考虑了其等价式及(p,q)-参数形式的推广情形.