Isometric copies of \(c_0\) and \(\ell^{\infty}\) in duals of Banach spaces
The author gives a simpler proof of the main result in another paper (yet to appear at the time of publication of the present one) which is concerned with the consequences of an ``asymptotically isometric'' copy of \(c_0\) being embedded in the dual of a Banach space. In particular, it is shown that this condition is equivalent to the existence of such an isometric copy of \(c_0\) and an isometric copy of \(\ell^\infty\) in the dual space. Moreover, this condition implies the existence of an isometric copy of \(\ell^\infty\) in the bidual as well.
scientific article; zbMATH DE number 1441398