1 research outputs found
Direct sums and the Szlenk index
For an ordinal and , we determine a necessary and
sufficient condition for an -direct sum of operators to have Szlenk
index not exceeding . It follows from our results that the
Szlenk index of an -direct sum of operators is determined in a natural
way by the behaviour of the -Szlenk indices of its summands. Our
methods give similar results for -direct sums.Comment: The proof of Proposition~2.4 has changed, with some of the arguments
transferred to the proof of an added-in lemma, Lemma~2.8. Changes have been
made to the Applications sectio