The Best Constants of Hardy Type Inequalities for $p=-1$
Received:March 28, 2006  Revised:December 12, 2006
Key Words: Hardy type inequalities   weight coefficient   the best constant.  
Fund Project:the National Natural Science Foundation of China (No.10671136); the Natural Science Foundation of Sichuan Provincial Education Department (No.2005A201).
Author NameAffiliation
WEN Jia Jin College of Mathematics and Information Science, Chengdu University, Sichuan 610106, China 
GAO Chao Bang College of Mathematics and Information Science, Chengdu University, Sichuan 610106, China 
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Abstract:
      For $p>1$, many improved or generalized results of the well-known Hardy's inequality have been established. In this paper, by means of the weight coefficient method, we establish the following Hardy type inequality for $p=-1$: $$ \sum_{i=1}^n\left(\frac{1}{i}\sum_{j=1}^ia_j\right)^{-1}<2\sum_{i=1}^n\left(1-\frac{\pi^2-9}{3i}\right)a_i^{-1}, $$ where $a_i>0,i=1,2,\ldots,n$. For any fixed positive integer $n\geq 2$, we study the best constant $C_n$ such that the inequality $\sum_{i=1}^n\left(\frac{1}{i}\sum_{j=1}^ia_j\right)^{-1}\leq C_n\sum_{i=1}^na_i^{-1}$ holds. Moreover, by means of the Mathematica software, we give some examples.
Citation:
DOI:10.3770/j.issn:1000-341X.2008.02.010
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