Results 181 to 190 of about 386,373 (206)

Compositions of Set Operations

Canadian Journal of Mathematics, 1970
The set operations under consideration are Borel operations and Souslin's operation (). With respect to a given family of sets and in a setting free of any topological structure there are defined three Borel families (Definitions 3.1) and the family of Souslin sets (Definition 4.1).
Bressler, D. W., Cayford, A. H.
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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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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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Composition Operators

Canadian Journal of Mathematics, 1968
The object of this note is to report on some of the properties of a class of operators induced by inner functions. If m is normalized Lebesgue measure on the unit circle X in the complex plane and Cϕ is an inner function (a complex function on X of unit modulus almost everywhere whose Poisson integral is a non-constant holomorphic function in the open ...
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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.
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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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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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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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GEOMETRIC QUANTITIES OF COMPOSITION OPERATORS

Far East Journal of Mathematical Sciences (FJMS), 2017
Summary: In this paper, we investigate geometric quantities of composition operators associated with various subclasses of univalent functions in the unit disk. We also consider applications of the quantities.
Kim, Yong Chan, Choi, Jae Ho
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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 f = H ∘ f {T_H}f = H \circ f need not be bounded on some of the Sobolev spaces (or spaces of Bessel potentials) even for very smooth functions H = H
Adams, David R., Frazier, Michael
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