Results 271 to 280 of about 38,889 (311)

Eigenvalues of Adjoints of Certain Composition Operators and Weighted Composition Operators

Integral Equations and Operator Theory, 2014
The paper is concerned with the spectral theory of composition operators on the Hardy space \(H^2\) of the unit disk. The author proves that, under certain conditions on the symbol \(\varphi \) (involving in particular fixed points), the point-spectrum of the adjoint \(C_\varphi^*\) of \(C_\varphi\) contains a disk centered at the origin.
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Considerations on Compositional Update Operators

2000
We develop two specific operators for modifying a knowledge base: Amend updates a knowledge base with a formula, while the complementary operator Forget removes a formula from the knowledge base. The approach differs from other belief change operators in that the definition of the operators is compositional with respect to the sentence added or removed.
James P. Delgrande, Matthew Suderman
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Commutators of composition operators with adjoints of composition operators on the ball

Complex Variables and Elliptic Equations, 2015
In this paper, we investigate compactness of the commutator on the Hardy space or the weighted Bergman space (), when and are automorphisms of the unit ball . We obtain that is compact if and only if both and are unitary and they commute. This generalizes the corresponding result in one variable. Moreover, our technique is different and simple.
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A model for composable composition operators

Proceedings of the 9th International Conference on Aspect-Oriented Software Development, 2010
A considerable amount of research, especially within the OO and AOSD communities, has focused on understanding the potential and limitations of various composition techniques. This has led to a large amount of proposals for alternative composition techniques, including many variations of message dispatch, inheritance, and aspect mechanisms.
Havinga, Wilke, Bergmans, Lodewijk, Akşit, Mehmet   +2 more
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Composition operators on potential spaces

Proceedings of the American Mathematical Society, 1992
By a result of B. Dahlberg, the composition operators T H
Adams, David R., Frazier, Michael
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Essential Norms of Composition Operators

Integral Equations and Operator Theory, 2004
Recently, there has been considerable interest in studying lower and upper estimates for the essential norms of composition operators in function spaces. Sometimes, as a consequence, a necessary and sufficient condition for the composition operator to be compact on the function space can be obtained.
Gorkin, Pamela, MacCluer, Barbara D.
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Operator regularization and composite operators

Canadian Journal of Physics, 1990
We demonstrate how operator regularization can be used to compute radiative corrections to Green's functions involving composite operators. No divergences are encountered and no symmetry-breaking regulating parameter need be introduced into the initial Lagrangian.
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UNIFORMLY BOUNDED COMPOSITION OPERATORS

Bulletin of the Australian Mathematical Society, 2015
We prove that if a uniformly bounded (or equidistantly uniformly bounded) Nemytskij operator maps the space of functions of bounded ${\it\varphi}$-variation with weight function in the sense of Riesz into another space of that type (with the same weight function) and its generator is continuous with respect to the second variable, then this generator ...
Głazowska, Dorota, Matkowski, Janusz
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Co-Rank of a Composition Operator

Canadian Mathematical Bulletin, 1986
AbstractA composition operator CT on L2(X, Σ,m) is a bounded linear transformation induced by a mapping T : X → X via CTf = f∘ T.If m has no atoms then the co-rank of CT (i.e., dim is either zero or infinite. As a corollary, when m has no atoms, CT is a Fredholm operator iff it is invertible.
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Implementations of program composition operations

1994
This paper reports on a number of implementations for a suite of composition operations of logic programs. We present and compare three implementations, which rely on different techniques: metaprogramming, program transformations, and extensions to the WAM, respectively.
Brogi A, Chiarelli A, Mancarella P, Mazzotta V, Pedreschi D, Renso C, Turini, F   +7 more
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