On the fundamental lemma of interpolation theory
The authors provide a new proof of a stronger version of the fundamental lemma of interpolation theory [see \textit{J. Bergh} and \textit{J. Löfström}, Interpolation spaces: An introduction p. 45 (1976; Zbl 0344.46071)], which gives the best known value of the constant \(\beta\), namely \(\beta =3+2\sqrt{2}\) as announced by A. A. Dmitriev. They also obtain a continuous version and an E-functional version of this strong fundamental lemma.
scientific article; zbMATH DE number 4136698
scientific article