For each ordinal α<ω1, we prove the existence of a space with a
basis and Szlenk index ωα+1 which is universal for the class of
spaces with Szlenk index not exceeding ωα. Our proof involves
developing a characterization of which Banach spaces embed into spaces with an
FDD with upper Schreier space estimates.Comment: arXiv admin note: text overlap with arXiv:0809.3626 by other author