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On the number of non isomorphic subspaces of a Banach space

Valentin Ferenczi·Christian Rosendal
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Abstract

If a Banach space has an unconditional basis it either contains a continuum of non isomorphic subspaces or is isomorphic to its square and hyperplanes and satisfies other regularity properties. An HI Banach space contains a continuum of non isomorphic subspaces.

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Valentin Ferenczi, Christian Rosendal. 2002-01-09. On the number of non isomorphic subspaces of a Banach space. https://arxiv.org/abs/math/0201072

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