A characterization of banach spaces containing L.
It is proved that a Banach space contains a subspace isomorphic to l(1) if (and only if) it has a bounded sequence with no weak-Cauchy subsequence. The proof yields that a sequence of subsets of a given set has a subsequence that is either convergent or Boolean independent.
Rosenthal
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HP
The Ohio State University, Columbus, Ohio 43210.