On weakly null FDD'S in Banach spaces Academic Article uri icon


  • In this paper we show that every sequence (F n ) of finite dimensional subspaces of a real or complex Banach space with increasing dimensions can be "refined" to yield an F.D.D. (G n ), still having increasing dimensions, so that either every bounded sequence (x n ), with x n ∈G n for n∈ℕ, is weakly null, or every normalized sequence (x n ),with x n ∈G n for n∈ℕ, is equivalent to the unit vector basis of ℓ1. Crucial to the proof are two stabilization results concerning Lipschitz functions on finite dimensional normed spaces. These results also lead to other applications. We show, for example, that every infinite dimensional Banach space X contains an F.D.D. (F n ),with lim n→∞dim(F n )=∞, so that all normalized sequences (x n ),with x n ∈F n, n∈/, have the same spreading model over X. This spreading model must necessarily be 1-unconditional over X. © 1993 The Magnes Press.

author list (cited authors)

  • Odell, E., Rosenthal, H. P., & Schlumprecht, T. h.

citation count

  • 6

publication date

  • October 1993