Research Article | Open Access
A Generalization on Some New Types of Hardy-Hilbert’s Integral Inequalities
Sulaiman presented, in 2008, new kinds of Hardy-Hilbert’s integral inequality in which the weight function is homogeneous. In this paper, we present a generalization on the kinds of Hardy-Hilbert’s integral inequality.
1. Introduction and Preliminaries
For any two nonnegative measurable functions and such that we have the Hilbert’s integral inequality  that The constant is the best possible. In 1925, Hardy  extended the Hilbert’s integral inequality into the integral inequality as follows. If , , and such that then we have the Hardy-Hilbert’s integral inequality that The constant is the best possible. Both the two inequalities are important in mathematical analysis and its applications .
In 1938, Widder  studied on the Stieltjes Transform .
Now, we recall the beta function as follows:
In 2001, Yang  extended the Hardy-Hilbert’s integral inequality into the following integral inequality. If , , , and such that
then we have where . The constant is the best possible.
We also recall that a nonnegative function which is said to be homogeneous function of degree if for all . And we say that is increasing if and are increasing functions.
In 2008, Sulaiman  gave new integral inequality similar to the Hardy-Hilbert’s integral inequality. If , , , , is a positive increasing homogeneous function of degree , and and then, for all , we have where
In this paper, we present a generalization of the integral inequality (9) and its applications. Next proposition will be used in the next section.
Proposition 1 (see ). Let be a positive increasing function, and . Then, for all , one has
2. Main Results
Theorem 2. Let , , , , and let be positive increasing homogeneous function of degree , and and
and let be a function such that for all .
Then, for all , one has where
Proof. Let and .
By the Hölder inequality, the assumption of , and the Tonelli theorem, we have
Now, we put and for the first integral, and then we put and for the second integral.
And, by Proposition 1, one has
Then, by the assumption, one has
This proof is completed.
Corollary 3. Let , , and , and let be a positive increasing homogeneous function of degree , and and
Then, for all , one has where
4. Open Problem
In this section, we pose a question that is how to generalize the integral inequality (13) if may not satisfy the property for all .
The author would like to thank the referees for their useful comments and suggestions.
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- G. H. Hardy, “Notes on a theorem of Hilbert concerning series of positive terms,” Proceedings of the London Mathematical Society, vol. 23, pp. 45–46, 1925.
- D. S. Mitrinović, J. E. Pečarić, and A. M. Fink, Inequalities Involving Functions and Their Integrals and Derivatives, vol. 53 of Mathematics and Its Applications (East European Series), Kluwer Academic Publishers, Dordrecht, The Netherlands, 1991.
- D. V. Widder, “The Stieltjes transform,” Transactions of the American Mathematical Society, vol. 43, no. 1, pp. 7–60, 1938.
- B. Yang, “On Hardy-Hilbert’s integral inequality,” Journal of Mathematical Analysis and Applications, vol. 261, pp. 295–306, 2001.
- W. T. Sulaiman, “A study on some new types of Hardy-Hilbert's integral inequalities,” Banach Journal of Mathematical Analysis, vol. 2, no. 1, pp. 16–20, 2008.
Copyright © 2013 Banyat Sroysang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.