The extension of the Krein-Šmulian theorem for order-continuous Banach lattices

Antonio S. Granero ; Marcos Sánchez

Banach Center Publications, Tome 83 (2008), p. 79-93 / Harvested from The Polish Digital Mathematics Library

Résumé

If X is a Banach space and C ⊂ X a convex subset, for x** ∈ X** and A ⊂ X** let d(x**,C) = inf||x**-x||: x ∈ C be the distance from x** to C and d̂(A,C) = supd(a,C): a ∈ A. Among other things, we prove that if X is an order-continuous Banach lattice and K is a w*-compact subset of X** we have: (i) $d̂(\overline{co}^{w*}(K),X) ≤ 2d̂(K,X)$ and, if K ∩ X is w*-dense in K, then $d̂(\overline{co}^{w*}(K),X) = d̂(K,X)$; (ii) if X fails to have a copy of ℓ₁(ℵ₁), then $d̂(\overline{co}^{w*}(K),X) = d̂(K,X)$; (iii) if X has a 1-symmetric basis, then $d̂(\overline{co}^{w*}(K),X) = d̂(K,X)$.

Détail

Publié le : 2008-01-01

Zbl 1144.46016

EUDML-ID : urn:eudml:doc:286276