On the unconditional subsequence property

Abstract

We show that a construction of Johnson, Maurey and Schechtman leads to the existence of a weakly null sequence (fi) in (∑ Lpi)ℓ2, where pi ↓ 1, so that for all ε > 0 and 1 < q ≤ 2, every subsequence of (fi) admits a block basis (1 + ε)-equivalent to the Haar basis for Lq. We give an example of a reflexive Banach space having the unconditional subsequence property but not uniformly so.

Publication Title

Journal of Functional Analysis

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