Displaying similar documents to “Outer factorization of operator valued weight functions on the torus”

Lifting properties, Nehari theorem and Paley lacunary inequality.

Mischa Cotlar, Cora Sadosky (1986)

Revista Matemática Iberoamericana

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A general notion of lifting properties for families of sesquilinear forms is formulated. These lifting properties, which appear as particular cases in many classical interpolation problems, are studied for the Toeplitz kernels in Z, and applied for refining and extending the Nehari theorem and the Paley lacunary inequality.

Pointwise multiplication operators on weighted Banach spaces of analytic functions

J. Bonet, P. Domański, M. Lindström (1999)

Studia Mathematica

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For a wide class of weights we find the approximative point spectrum and the essential spectrum of the pointwise multiplication operator M φ , M φ ( f ) = φ f , on the weighted Banach spaces of analytic functions on the disc with the sup-norm. Thus we characterize when M φ ' is Fredholm or is an into isomorphism. We also study cyclic phenomena for the adjoint map M φ ' .

Generalization of the Newman-Shapiro isometry theorem and Toeplitz operators. II

Dariusz Cichoń (2002)

Studia Mathematica

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The Newman-Shapiro Isometry Theorem is proved in the case of Segal-Bargmann spaces of entire vector-valued functions (i.e. summable with respect to the Gaussian measure on ℂⁿ). The theorem is applied to find the adjoint of an unbounded Toeplitz operator T φ with φ being an operator-valued exponential polynomial.

Toeplitz operators in the commutant of a composition operator

Bruce Cload (1999)

Studia Mathematica

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If ϕ is an analytic self-mapping of the unit disc D and if H 2 ( D ) is the Hardy-Hilbert space on D, the composition operator C ϕ on H 2 ( D ) is defined by C ϕ ( f ) = f ∘ ϕ . In this article, we consider which Toeplitz operators T f satisfy T f C ϕ = C ϕ T f

Spectral approximation for Segal-Bargmann space Toeplitz operators

Albrecht Böttcher, Hartmut Wolf (1997)

Banach Center Publications

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Let A stand for a Toeplitz operator with a continuous symbol on the Bergman space of the polydisk N or on the Segal-Bargmann space over ℂ N . Even in the case N = 1, the spectrum Λ(A) of A is available only in a few very special situations. One approach to gaining information about this spectrum is based on replacing A by a large “finite section”, that is, by the compression A n of A to the linear span of the monomials z 1 k 1 . . . z N k N : 0 ≤ k j ≤ n . Unfortunately, in general the spectrum of A n does not mimic the spectrum...

Weighted inequalities through factorization.

Eugenio Hernández (1991)

Publicacions Matemàtiques

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In [4] P. Jones solved the question posed by B. Muckenhoupt in [7] concerning the factorization of Ap weights. We recall that a non-negative measurable function w on Rn is in the class Ap, 1 < p < ∞ if and only if the Hardy-Littlewood maximal operator is bounded on Lp(Rn, w). In what follows, Lp(X, w) denotes the class of all measurable functions f defined...

Vector-valued inequalities with weights.

Luz M. Fernández-Cabrera, José L. Torrea (1993)

Publicacions Matemàtiques

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This paper deals with the following problem: Let T be a given operator. Find conditions on v(x) (resp. u(x)) such that ∫ |Tf(x)|pu(x) dx ≤ C ∫ |f(x)|pv(x) dx is satisfied for some u(x) (resp. v(x)). Using vector-valued inequalities the problem is solved for: Carleson's maximal operator of Fourier partial sums, Littlewood-Paley square functions, Hilbert transform of functions...