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A note on a “Hardy-type” inequality. (English) Zbl 0703.26016

A generalization, involving certain continuous increasing functions, of the “Hardy-type” inequality \[ (*)\quad \frac{1}{\ell}\int^{\ell}_{0}(\frac{1}{t}\int^{t}_{0}f(s)ds)^{r/ q}dt\leq \frac{q}{q-r}(\frac{1}{\ell}\int^{\ell}_{0}f(s)ds)^{r/q}, \] (f\(\in L^ 1(0,\ell)\), \(f\geq 0\), \(1\leq r<q)\) is proved. The constant in (*) is the best possible.
Reviewer: A.Fiorenza

MSC:

26D15 Inequalities for sums, series and integrals