For a countable ordinal α we denote by the class of separable, reflexive Banach spaces whose Szlenk index and the Szlenk index of their dual are bounded by α. We show that each admits a separable, reflexive universal space. We also show that spaces in the class embed into spaces of the same class with a basis. As a consequence we deduce that each is analytic in the Effros-Borel structure of subspaces of C[0,1].
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm183-1-4, author = {E. Odell and Th. Schlumprecht and A. Zs\'ak}, title = {Banach spaces of bounded Szlenk index}, journal = {Studia Mathematica}, volume = {178}, year = {2007}, pages = {63-97}, zbl = {1138.46005}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm183-1-4} }
E. Odell; Th. Schlumprecht; A. Zsák. Banach spaces of bounded Szlenk index. Studia Mathematica, Tome 178 (2007) pp. 63-97. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm183-1-4/