We study interpolation spaces between global Morrey spaces and between local Morrey spaces. We prove that for a wide class of couples of these spaces the upper complex Calderón spaces are not described by the -method of interpolation. A by-product of our results is that couples of Morrey spaces belonging to this class are not Calderón–Mityagin couples. A Banach couple is said to have the universal -property if all relative interpolation spaces from any Banach couple to are relatively -monotone. A couple of local Morrey spaces is proved to have the universal -property once it is a Calderón–Mityagin couple.
"Complex interpolation and Calderón–Mityagin couples of Morrey spaces." Anal. PDE 12 (7) 1711 - 1740, 2019. https://doi.org/10.2140/apde.2019.12.1711