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On the Stieltjes moment problem on semigroups

Torben Maack Bisgaard (2002)

Czechoslovak Mathematical Journal

We characterize finitely generated abelian semigroups such that every completely positive definite function (a function all of whose shifts are positive definite) is an integral of nonnegative miltiplicative real-valued functions (called nonnegative characters).

On the two weights problem for the Hilbert transform.

Nets Hawk Katz, Cristina Pereyra (1997)

Revista Matemática Iberoamericana

In this paper, we prove sufficient conditions on pairs of weights (u,v) (scalar, matrix or operator valued) so that the Hilbert transform H f(x) = p.v. ∫ [f(y) / x - y] dy,is bounded from L2(u) to L2(v).

On the Uniform Convergence of Partial Dunkl Integrals in Besov-Dunkl Spaces

Abdelkefi, Chokri, Sifi, Mohamed (2006)

Fractional Calculus and Applied Analysis

2000 Mathematics Subject Classification: 44A15, 44A35, 46E30In this paper we prove that the partial Dunkl integral ST(f) of f converges to f, as T → +∞ in L^∞(νµ) and we show that the Dunkl transform Fµ(f) of f is in L^1(νµ) when f belongs to a suitable Besov-Dunkl space. We also give sufficient conditions on a function f in order that the Dunkl transform Fµ(f) of f is in a L^p -space.* Supported by 04/UR/15-02.

On Y. Nievergelt's Inversion Formula for the Radon Transform

Ournycheva, E., Rubin, B. (2010)

Fractional Calculus and Applied Analysis

Mathematics Subject Classification 2010: 42C40, 44A12.In 1986 Y. Nievergelt suggested a simple formula which allows to reconstruct a continuous compactly supported function on the 2-plane from its Radon transform. This formula falls into the scope of the classical convolution-backprojection method. We show that elementary tools of fractional calculus can be used to obtain more general inversion formulas for the k-plane Radon transform of continuous and L^p functions on R^n for all 1 ≤ k < n....

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