Some linear topological properties of the hardy spaces
We prove that if is not a Kunen cardinal, then there is a uniform Eberlein compact space K such that the Banach space C(K) does not embed isometrically into . We prove a similar result for isomorphic embeddings. Our arguments are minor modifications of the proofs of analogous results for Corson compacta obtained by S. Todorčević. We also construct a consistent example of a uniform Eberlein compactum whose space of continuous functions embeds isomorphically into , but fails to embed isometrically....
We take another approach to the well known theorem of Korovkin, in the following situation: X, Y are compact Hausdorff spaces, M is a unital subspace of the Banach space C(X) (respectively, ) of all complex-valued (resp., real-valued) continuous functions on X, S ⊂ M a complex (resp., real) function space on X, ϕₙ a sequence of unital linear contractions from M into C(Y) (resp., ), and a linear isometry from M into C(Y) (resp., ). We show, under the assumption that , where is the Choquet...
We study the structure of Lipschitz and Hölder-type spaces and their preduals on general metric spaces, and give applications to the uniform structure of Banach spaces. In particular we resolve a problem of Weaver who asks wether if M is a compact metric space and 0 < α < 1, it is always true the space of Hölder continuous functions of class α is isomorphic to l∞. We show that, on the contrary, if M is a compact convex subset of a Hilbert space this isomorphism holds if and only if...
Let be a complex Banach space, with the unit ball . We study the spectrum of a bounded weighted composition operator on determined by an analytic symbol with a fixed point in such that is a relatively compact subset of , where is an analytic function on .
Let be a sequence of positive numbers and . We consider the space of all power series such that . We investigate strict cyclicity of , the weakly closed algebra generated by the operator of multiplication by acting on , and determine the maximal ideal space, the dual space and the reflexivity of the algebra . We also give a necessary condition for a composition operator to be bounded on when is strictly cyclic.