Nouvelles classes d'espaces de Banach à prédual unique
The three space problem for smooth partitions of unity and C(K) spaces.
On subspaces of L1 which embed into ...1.
Unconditional ideals in Banach spaces
We show that a Banach space with separable dual can be renormed to satisfy hereditarily an “almost” optimal uniform smoothness condition. The optimal condition occurs when the canonical decomposition is unconditional. Motivated by this result, we define a subspace X of a Banach space Y to be an h-ideal (resp. a u-ideal) if there is an hermitian projection P (resp. a projection P with ∥I-2P∥ = 1) on Y* with kernel . We undertake a general study of h-ideals and u-ideals. For example we show that...
Lipschitz-free Banach spaces
We show that when a linear quotient map to a separable Banach space X has a Lipschitz right inverse, then it has a linear right inverse. If a separable space X embeds isometrically into a Banach space Y, then Y contains an isometric linear copy of X. This is false for every nonseparable weakly compactly generated Banach space X. Canonical examples of nonseparable Banach spaces which are Lipschitz isomorphic but not linearly isomorphic are constructed. If a Banach space X has the bounded approximation...
Isometric embeddings and universal spaces.
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