Cobos Díaz, FernandoCwikel, M.Kühn, Thomas2023-06-222023-06-222022-08-280022-247X10.1016/j.jmaa.2022.126634https://hdl.handle.net/20.500.14352/71924CRUE-CSIC (Acuerdos Transformativos 2022)We prove that, under a mild condition on a couple (A0;A1) of quasi-Banach spaces, all real interpolation spaces (A0;A1)θ,p with 0 < θ < 1 and 0 < p ≤ ∞ are different from each other. In the Banach case and for 1 ≤ p ≤ ∞ this was shown by Janson, Nilsson, Peetre and Zafran, thus solving an old problem posed by J.-L. Lions. Moreover, we give an application to certain spaces which are important objects in Operator Theory and which consist of bounded linear operators whose approximation numbers belong to Lorentz sequence spaces.engAtribución-NoComercial-SinDerivadas 3.0 Españahttps://creativecommons.org/licenses/by-nc-nd/3.0/es/journal articlehttps://doi.org/10.1016/j.jmaa.2022.126634open access517.98Real interpolationK-functionalDependence on the parametersSpaces of operators defined by approximation numbers.Análisis funcional y teoría de operadores