The universality of ℓ1 as a dual space

  title={The universality of ℓ1 as a dual space},
  author={Daniel Freeman and Edward Odell and Th. Schlumprecht},
  journal={Mathematische Annalen},
Let X be a Banach space with a separable dual. We prove that X embeds isomorphically into a $${{\mathcal L}_\infty}$$ space Z whose dual is isomorphic to ℓ1. If, moreover, U is a space with separable dual, so that U and X are totally incomparable, then we construct such a Z, so that Z and U are totally incomparable. If X is separable and reflexive, we show that Z can be made to be somewhat reflexive.