%0 Journal Article
%A Cobos Díaz, Fernando
%A Cwikel, M.
%A Kühn, Thomas
%T On a problem of Lions concerning real interpolation spaces. The quasi-Banach case
%D 2022
%@ 0022-247X
%U https://hdl.handle.net/20.500.14352/71924
%X 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.
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