Complex interpolation of Orlicz sequence spaces and its higher order Rochberg spaces

Abstract

We show that if $({\ell }_{{\varphi }_0},{\ell }_{{\varphi }_1})$ is a couple of suitable Orlicz sequence spaces then the corresponding Rochberg derived spaces of all orders associated to the complex interpolation method are Fenchel-Orlicz spaces. In particular, the induced twisted sums have the $(C[0,1],\mathbb{C})$-extension property.

11 pages. Minor corrections and restructuration of the paper