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A two weight weak inequality for potential type operators

Vachtang Michailovič Kokilashvili, Jiří Rákosník (1991)

Commentationes Mathematicae Universitatis Carolinae

We give conditions on pairs of weights which are necessary and sufficient for the operator T ( f ) = K * f to be a weak type mapping of one weighted Lorentz space in another one. The kernel K is an anisotropic radial decreasing function.

A two-weight inequality for the Bessel potential operator

Yves Rakotondratsimba (1997)

Commentationes Mathematicae Universitatis Carolinae

Necessary conditions and sufficient conditions are derived in order that Bessel potential operator J s , λ is bounded from the weighted Lebesgue spaces L v p = L p ( n , v ( x ) d x ) into L u q when 1 < p q < .

A uniform estimate for quartile operators.

Christoph Thiele (2002)

Revista Matemática Iberoamericana

There is a one parameter family of bilinear Hilbert transforms. Recently, some progress has been made to prove Lp estimates for these operators uniformly in the parameter. In the current article we present some of these techniques in a simplified model...

A variant sharp estimate for multilinear singular integral operators

Guoen Hu, Dachun Yang (2000)

Studia Mathematica

We establish a variant sharp estimate for multilinear singular integral operators. As applications, we obtain the weighted norm inequalities on general weights and certain L l o g + L type estimates for these multilinear operators.

A variation norm Carleson theorem

Richard Oberlin, Andreas Seeger, Terence Tao, Christoph Thiele, James Wright (2012)

Journal of the European Mathematical Society

We strengthen the Carleson-Hunt theorem by proving L p estimates for the r -variation of the partial sum operators for Fourier series and integrals, for r > 𝚖𝚊𝚡 { p ' , 2 } . Four appendices are concerned with transference, a variation norm Menshov-Paley-Zygmund theorem, and applications to nonlinear Fourier transforms and ergodic theory.

A version of the law of large numbers

Katusi Fukuyama (2001)

Colloquium Mathematicae

By the method of Rio [10], for a locally square integrable periodic function f, we prove ( f ( μ t x ) + . . . + f ( μ t x ) ) / n 0 1 f for almost every x and t > 0.

A wavelet characterization for weighted Hardy spaces.

Si Jue Wu (1992)

Revista Matemática Iberoamericana

In this article we give a wavelet area integral characterization for weighted Hardy spaces Hp(ω), 0 &lt; p &lt; ∞, with ω ∈ A∞. Our wavelet characterization establishes the identification between Hp(ω) and T2p (ω), the weighted discrete tent space, for 0 &lt; p &lt; ∞ and ω ∈ A∞. This allows us to use all the results of tent spaces for weighted Hardy spaces. In particular, we obtain the isomorphism between Hp(ω) and the dual space of Hp'(ω), where 1&lt; p &lt; ∞ and 1/p +...

A way of estimating the convergence rate of the Fourier method for PDE of hyperbolic type

Evgenii Pustylnik (2001)

Czechoslovak Mathematical Journal

The Fourier expansion in eigenfunctions of a positive operator is studied with the help of abstract functions of this operator. The rate of convergence is estimated in terms of its eigenvalues, especially for uniform and absolute convergence. Some particular results are obtained for elliptic operators and hyperbolic equations.

A weak molecule condition for certain Triebel-Lizorkin spaces

Steve Hofmann (1992)

Studia Mathematica

A weak molecule condition is given for the Triebel-Lizorkin spaces Ḟ_p^{α,q}, with 0 < α < 1 and 1 < p, q < ∞. As an easy corollary, one may deduce, by atomic-molecular methods, a Triebel-Lizorkin space "T1" Theorem of Han and Sawyer, and Han, Jawerth, Taibleson and Weiss, for Calderón-Zygmund kernels K(x,y) which are not assumed to satisfy any regularity condition in the y variable.

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