Results 21 to 30 of about 54,827 (267)
Local spectral theory of endomorphisms of the disk algebra
Demonstratio Mathematica, 2016 Let A(𝔻) denote the disk algebra. Every endomorphism of A(𝔻) is induced by some ϕ ∈ A(𝔻) with ‖ϕ‖ ≤ 1. In this paper, it is shown that if ϕ is not an automorphism of 𝔻 and ϕ has a fixed point in the open unit disk then the endomorphism induced by ϕ is ...
Trivedi Shailesh, Chandra Harish
doaj +1 more source
Composition Operator on Bergman-Orlicz Space
Journal of Inequalities and Applications, 2009 Let denote the open unit disk in the complex plane and let denote the normalized area measure on . For and a twice differentiable, nonconstant, nondecreasing, nonnegative, and convex function on , the Bergman-Orlicz space is defined as ...
Jiang Zhijie, Cao Guangfu
doaj +2 more sources
The Composition operator induced by a polynomial of degree n
مجلة بغداد للعلوم, 2011 In this paper, we characterize normal composition operators induced by holomorphic self-map , when and .Moreover, we study other related classes of operators, and then we generalize these results to polynomials of degree n.
Baghdad Science Journal
doaj +1 more source
Skew-symmetric and essentially unitary operators via Berezin symbols
Open Mathematics, 2020 We characterize skew-symmetric operators on a reproducing kernel Hilbert space in terms of their Berezin symbols. The solution of some operator equations with skew-symmetric operators is studied in terms of Berezin symbols.
Altwaijry Najla +3 more
doaj +1 more source
Hermitian composition operators on Hardy-Smirnov spaces
Concrete Operators, 2017 Let Ω be an open simply connected proper subset of the complex plane and φ an analytic self map of Ω. If f is in the Hardy-Smirnov space defined on Ω, then the operator that takes f to f º φ is a composition operator.
Gunatillake Gajath
doaj +1 more source
Approximation numbers of composition operators on Hp
Concrete Operators, 2015 give estimates for the approximation numbers of composition operators on the Hp spaces, 1 ≤ p < ∞
Li Daniel +2 more
doaj +1 more source
Composite operators in QCD [PDF]
Nuclear Physics B, 1992 We give a formula for the derivatives of a correlation function of composite operators with respect to the parameters (i.e., the strong fine structure constant and the quark mass) of QCD in four-dimensional euclidean space. The formula is given as spatial integration of the operator conjugate to a parameter. The operator product of a composite operator
openaire +2 more sources
Jan Stochel, a stellar mathematician [PDF]
Opuscula MathematicaThe occasion for this survey article was the 70th birthday of Jan Stochel, professor at Jagiellonian University, former head of the Chair of Functional Analysis and a prominent member of the Kraków school of operator theory.
Sameer Chavan +4 more
doaj +1 more source
Compact composition operators [PDF]
Journal of the Australian Mathematical Society, 1979 AbstractLet (Хζ,λ) be a σ-finite measure space, and let ϕ be a non-singular measurable transformation from X into itself. Then a composition transformation Cϕ on L2(λ) is defined by Cϕf = f ∘ ϕ. If Cϕ is a bounded operator, then it is called a composition operator.
Singh, R. K., Kumar, Ashok
openaire +2 more sources
Universal composition operators
Journal of Operator Theory, 2021 A Hilbert space operator U is called \textit{universal} (in the sense of Rota) if every Hilbert space operator is similar to a multiple of U restricted to one of its invariant subspaces. It follows that the \textit{invariant subspace problem} for Hilbert spaces is equivalent to the statement that all minimal invariant subspaces for U are one ...
Carmo, João R., Noor, S. Waleed
openaire +2 more sources