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arXiv · 2203.10500

Some examples of equivalent rearrangement-invariant quasi-norms defined via f* or f**

Leo R. Ya. Doktorski·Pedro Fernández-Martínez·Teresa Signes
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Abstract

We consider Lorentz-Karamata spaces, small and grand Lorentz-Karamata spaces, and the so-called $\mathcal{L}$, $\mathcal{R}$, $\mathcal{LL}$, $\mathcal{RL}$, $\mathcal{RL}$, and $\mathcal{RR}$ spaces. The quasi-norms for a function $f$ in each of these spaces can be defined via the non-increasing rearrangement $f^*$ or via the maximal function $f^{**}$. We investigate when these quasi-norms are equivalent. Most of the proofs are based on Hardy-type inequalities. As application we demonstrate how our general results can be used to establish interpolation formulae for the grand and small Lorentz-Karamata spaces.

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Leo R. Ya. Doktorski, Pedro Fernández-Martínez, Teresa Signes. 2022-03-20. Some examples of equivalent rearrangement-invariant quasi-norms defined via f* or f**. https://arxiv.org/abs/2203.10500

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