A Banach Subspace of L 1 / 2 Which Does Not Embed In
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چکیده
For every n ≥ 3, we construct an n-dimensional Banach space which is isometric to a subspace of L1/2 but is not isometric to a subspace of L1. The isomorphic version of this problem (posed by S. Kwapien in 1969) is still open. Another example gives a Banach subspace of L1/4 which does not embed isometrically in L1/2. Note that, from the isomorphic point of view, all the spaces Lq with q < 1 have the same Banach subspaces.
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تاریخ انتشار 1994