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arXiv · 2001.06165

On the stability of the Lions-Peetre method of real interpolation with functional parameter

Amiran Gogatishvili
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Abstract

Let $\vec{X}=(X_0, X_1)$ be a compatible couple of Banach spaces, $ 1\le p \le \infty$ and let $ \varphi$ be positive quasi-concave function. Denote by $\overline{X}_{\varphi,p}=(X_0,X_1)_{\varphi,p}$ the real interpolation spaces defined by S. Janson (1981). We give necessary and sufficient conditions on $ \varphi_{0}$, $\varphi_{1}$ and $\varphi$ for the validity of \begin{equation*} \left(\overline{X}_{\varphi_{0},1},\overline{X}_{\varphi_{1},1} \right) _{\varphi,p}= \left(\overline{X}_{\varphi_{0},\infty},\overline{X}_{\varphi_{1},\infty}\right)_{\varphi,p} \end{equation*} for all $ 1\le p\le \infty$, and all Banach couples $\overline{X}. $

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Amiran Gogatishvili. 2020-01-17. On the stability of the Lions-Peetre method of real interpolation with functional parameter. https://arxiv.org/abs/2001.06165

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