We consider differences of weighted composition operators between given weighted Bergman spaces H∞ v of infinite order and characterize boundedness and the essential norm of these differences.

in this paper we obtain lower and upper estimates for the essential norms of generalized composition operators from weighted dirichlet spaces or bloch type spaces to $q_k$ type spaces.

We study when weighted composition operators Cφ,ψ acting between weighted Bergman spaces of infinite order are power bounded resp. uniformly mean ergodic.

Program composition and compositional proof systems have proven them­ selves important for simplifying the design and the verification of programs. The paper presents a version of the jigsaw program composition operator pre­ viously defined in [FFG90, FFG91]. Here, the jigsaw operator is defined as the unification of its components by their most general unifier. The jigsaw operator generalizes ...

We undertake a systematic study of cyclic phenomena for composition operators. Our work shows that composition operators exhibit strikingly diverse types of cyclic behavior, and it connects this behavior with classical problems involving complex polynomial approximation and analytic functional equations. Received by the editor January 25, 1994

If φ is an analytic map of the unit diskD into itself, the composition operator Cφ on the Hardy space H (D) is defined by Cφ(f) = f ◦ φ. For a certain class of composition operators with multivalent symbol φ, we identify a subspace of H(D) on which C∗ φ behaves like a weighted shift. We reproduce the description of the spectrum found in [5] and show for this class of composition operators that ...

Composition operators C− between Orlicz spaces L.;6;1⁄4/ generated by measurable and nonsingular transformations − from  into itself are considered. We characterize boundedness and compactness of the composition operator between Orlicz spaces in terms of properties of the mapping − , the function ' and the measure space .;6;1⁄4/. These results generalize earlier results known for L p-spaces....

Let C , be a composition operator on L (A). Some conditions under which C, is an isometry and Hermitian are investigated in this paper. Some study of normal composition operators is also made.

In this paper, we estimate essential norms of weighted composition operators and differences two on the Bergman spaces in unit ball.