On some classes of linear topological spaces
Two problems posed by Choquet and Foias are solved:(i) Let be a positive linear operator on the space of continuous real-valued functions on a compact Hausdorff space . It is shown that if converges pointwise to a continuous limit, then the convergence is uniform on .(ii) An example is given of a Choquet simplex and a positive linear operator on the space of continuous affine real-valued functions on , such thatfor each in , but does not converge to 0.
In this article, we consider the (weak) drop property, weak property (a), and property (w) for closed convex sets. Here we give some relations between those properties. Particularly, we prove that C has (weak) property (a) if and only if the subdifferential mapping of Cº is (n-n) (respectively, (n-w)) upper semicontinuous and (weak) compact valued. This gives an extension of a theorem of Giles and the first author.
It is proved that if a Kothe sequence space is monotone complete and has the weakly convergent sequence coefficient WCS, then is order continuous. It is shown that a weakly sequentially complete Kothe sequence space is compactly locally uniformly rotund if and only if the norm in is equi-absolutely continuous. The dual of the product space of a sequence of Banach spaces , which is built by using an Orlicz function satisfying the -condition, is computed isometrically (i.e. the exact...
We show several characterizations of weakly compact sets in Banach spaces. Given a bounded closed convex set C of a Banach space X, the following statements are equivalent: (i) C is weakly compact; (ii) C can be affinely uniformly embedded into a reflexive Banach space; (iii) there exists an equivalent norm on X which has the w2R-property on C; (iv) there is a continuous and w*-lower semicontinuous seminorm p on the dual X* with such that p² is everywhere Fréchet differentiable in X*; and as a...