Α-minimal Banach Spaces
نویسنده
چکیده
A Banach space W with a Schauder basis is said to be α-minimal for some α < ω1 if, for any two block subspaces Z,Y ⊆ W, the Bourgain embeddability index of Z into Y is at least α. We prove a dichotomy that characterises when a Banach space has an αminimal subspace, which contributes to the ongoing project, initiated by W. T. Gowers, of classifying separable Banach spaces by identifying characteristic subspaces.
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