Results 301 to 310 of about 4,584,260 (359)

Norm and Essential Norm of a Weighted Composition Operator on the Bloch Space

, 2015
Some new estimates for the norm and essential norm of a weighted composition operator on the Bloch space are given in this paper.
Xiaosong Liu, Songxiao Li
semanticscholar   +1 more source

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.
openaire   +1 more source

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
openaire   +1 more source

Continuity of the Norm of a Composition Operator

Integral Equations and Operator Theory, 2003
Let \(ASM({\mathbb{D}})^1\) (respectively, \(ASM({\mathbb{D}})^\infty\)) denote the set of all analytic self-maps of the unit disc, considered as a subset of \(H^1\) (respectively, \(H^\infty \)). Let \(N_i: ASM({\mathbb{D}})^i \to {\mathbb{R}}\) (\(i=1, \infty \)) be given by \(N_i(\varphi )= \| C_\varphi \|\), where \(C_\varphi \) is the composition ...
D. Pokorny, J. E. Shapiro
semanticscholar   +2 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 \(Wf:=\phi f\circ T\).
openaire   +2 more sources

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 ...
openaire   +1 more source

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

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.
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.
openaire   +2 more sources

Dynamic Mode Decomposition for Continuous Time Systems with the Liouville Operator

Journal of nonlinear science, 2019
Dynamic mode decomposition (DMD) has become synonymous with the Koopman operator, where continuous time dynamics are discretized and examined using Koopman (i.e. composition) operators.
Joel A. Rosenfeld, R. Kamalapurkar, L. Gruss, Taylor T. Johnson   +3 more
semanticscholar   +1 more source