The Szegö and Beurling theorems and operator factorizations
If ϕ is an analytic self-mapping of the unit disc D and if is the Hardy-Hilbert space on D, the composition operator on is defined by . In this article, we consider which Toeplitz operators satisfy
We study Toeplitz operators with radial symbols in weighted Bergman spaces , 1 < p < ∞, on the disc. Using a decomposition of into finite-dimensional subspaces the operator can be considered as a coefficient multiplier. This leads to new results on boundedness of and also shows a connection with Hardy space multipliers. Using another method we also prove a necessary and sufficient condition for the boundedness of for a satisfying an assumption on the positivity of certain indefinite...
Toeplitz quantization is defined in a general setting in which the symbols are the elements of a possibly non-commutative algebra with a conjugation and a possibly degenerate inner product. We show that the quantum group is such an algebra. Unlike many quantization schemes, this Toeplitz quantization does not require a measure. The theory is based on the mathematical structures defined and studied in several recent papers of the author; those papers dealt with some specific examples of this new...
In this survey article we describe how the recent work in quantization in multi-variable complex geometry (domains of holomorphy, symmetric domains, tube domains, etc.) leads to interesting results and problems in C*-algebras which can be viewed as examples of the "non-commutative geometry" in the sense of A. Connes. At the same time, one obtains new functional calculi (of pseudodifferential type) with possible applications to partial differential equations and group representations.