Results 261 to 270 of about 2,962,628 (305)

Composition Operators

2023
AbstractWe cover representative results concerning the boundedness, compactness, and spectral properties of composition operators.
Stephan Ramon Garcia, Javad Mashreghi, William T. Ross   +2 more
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Event composition operators

Proceedings of the 1st ACM international workshop on Events in multimedia, 2009
Events are at least as important as objects in modeling the dynamic universe. Modeling the real world and weaving the web of events require Composite Events that are valid constitution of atomic and composite sub-events. The progress in event composition has been limited to construction of some entities and relationships in upper ontologies such as ...
Setareh Rafatirad, Amarnath Gupta, Ramesh C. Jain   +2 more
openaire   +2 more sources

Operations and compositions in transrecursive operators

Cybernetics and Systems Analysis, 1994
Earlier, the authors introduced classes of alphabetic operators that have greater computational possibilities than classical algorithms. In Dokl. Akad. Nauk SSSR 321, No. 5, 876-879 (1991), they gave a uniform procedure for obtaining such alphabetic operators, which will be called transrecursive operators in what follows.
Burgin, M. S., Borodyanskij, Yu. M.
openaire   +3 more sources

Hyponormal Composition Operators

Bulletin of the London Mathematical Society, 1986
Let (X,\(\Sigma\),m) be a complete \(\sigma\)-finite measure space, and let T be a \(\Sigma\)-measurable mapping in X such that \(m\circ T^{-1}\) is absolutely continuous with respect to m. The corresponding weighted composition operator W on \(L^ 2(X,\Sigma,m)\) generated by the weight function \(\phi\) is defined by \(Wf:=\phi f\circ T\).
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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
openaire   +3 more sources

Composite Operations and Reconstruction

JAMA: The Journal of the American Medical Association, 1971
The present concept regarding defects of the head and neck that are created by cancer therapy is that they require immediate reconstruction. Prior to 1940, the majority of extensive tumors in this region were treated by radiation or cautery. Restoration of the area destroyed by invading cancer cells or therapy was delayed for six months or more.
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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
openaire   +2 more sources

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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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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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.
openaire   +1 more source