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哈代不等式


{a_n} 为一个非负 序列f(x) 为一个非负可积函数。定义

 A_n=sum_(k=1)^na_k
(1)

 F(x)=int_0^xf(t)dt
(2)

并取 p>1。 对于求和,

 sum_(n=1)^infty((A_n)/n)^p<(p/(p-1))^psum_(n=1)^infty(a_n)^p
(3)

(除非所有 a_n=0), 以及对于积分,

 int_0^infty[(F(x))/x]^pdx<(p/(p-1))^pint_0^infty[f(x)]^pdx
(4)

(除非 f 恒等于 0)。


另请参阅

卡尔曼不等式

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参考文献

Broadbent, T. A. A. "A Proof of Hardy's Convergence Theorem." J. London Math. Soc. 3, 232-243, 1928.Elliot, E. B. "A Simple Exposition of Some Recently Proved Facts as to Convergency." J. London Math. Soc. 1, 93-96, 1926.Grandjot, K. "On Some Identities Relating to Hardy's Convergence Theorem." J. London Math. Soc. 3, 114-117, 1928.Hardy, G. H. "Note on a Theorem of Hilbert." Math. Z. 6, 314-317, 1920.Hardy, G. H. "Notes on Some Points in the Integral Calculus. LX." Messenger Math. 54, 150-156, 1925.Hardy, G. H.; Littlewood, J. E.; and Pólya, G. "Hardy's Inequality." §9.8 in Inequalities, 2nd ed. Cambridge, England: Cambridge University Press, pp. 239-243, 1988.Kaluza, T. and Szegö, G. "Über Reihen mit lauter positiven Gliedern." J. London Math. Soc. 2, 266-272, 1927.Knopp, K. "Über Reihen mit positiven Gliedern." J. London Math. Soc. 3, 205-211, 1928.Landau, E. "A Note on a Theorem Concerning Series of Positive Terms." J. London Math. Soc. 1, 38-39, 1926.Mitrinovic, D. S.; Pecaric, J. E.; and Fink, A. M. Inequalities Involving Functions and Their Integrals and Derivatives. New York: Kluwer, 1991.Opic, B. and Kufner, A. Hardy-Type Inequalities. Essex, England: Longman, 1990.

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哈代不等式

请引用为

Weisstein, Eric W. "哈代不等式。" 来自 MathWorld-- Wolfram Web 资源。 https://mathworld.net.cn/HardysInequality.html

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