We study the boundedness and compactness of the differences of two weighted composition operators acting from the Bloch space B to the space H∞ of bounded analytic functions on the open unit disk. Such a study has a relationship to the topological structure problem of composition operators on H∞. Using this relation, we will estimate the operator norms and the essential norms of the differences...

A function theoretic characterization is given of when a composition operator is compact on BMOA, the space of analytic functions on the unit disk having radial limits that are of bounded mean oscillation on the unit circle. When the symbol of the composition operator is univalent, compactness on BMOA is shown to be equivalent to compactness on the Bloch space, and a characterization in terms o...

We present some characterizations for the compactness of difference two composition operators acting between analytic Besov spaces and weighted little Bloch type space over unit disk.

Let φ(z) = (φ1(z), · · · , φn(z)) be a holomorphic selfmap of B and ψ(z) a holomorphic function on B, where B is the unit ball of C n . Let 0 < p, s < +∞,−n− 1 < q < +∞, q+ s > −1 and α ≥ 0, this paper gives some necessary and sufficient conditions for the weighted composition operatorWψ,φ induced by φ and ψ to be bounded and compact between the space F (p, q, s) and α-Bloch space β.

We develop methods for constructing explicit generators, modulo torsion, of the K_3-groups imaginary quadratic number fields. These are based on either tessellations hyperbolic 3-space or direct calculations in suitable pre-Bloch groups, and lead to very first proven examples any infinite K_3-group a field. As part this approach, we make several improvements theory Bloch groups K_3 field, predi...