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  1. Article

    Open Access

    How to compute multivariate Bessel expansions

    We develop a constructive method for computing explicitly multivariate Bessel expansions of the type $$\begin{aligned} \sum _{m\ge 1} \alpha _...

    Antonio J. Durán, Mario Pérez, Juan L. Varona in The Ramanujan Journal (2024)

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    Article

    Superattracting Extraneous Fixed Points and n-cycles for Chebyshev’s Method on Cubic Polynomials

    In this work we provide analytic and graphic arguments to explain the behaviour of Chebyshev’s method applied to cubic polynomials in the complex plane. In particular, we study the parameter plane related to t...

    José M. Gutiérrez, Juan L. Varona in Qualitative Theory of Dynamical Systems (2020)

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    Article

    Bernoulli–Dunkl and Euler–Dunkl polynomials and their generalizations

    Bernoulli–Dunkl and Euler–Dunkl polynomials are generalizations of the classical Bernoulli and Euler polynomials, using the Dunkl operator instead of the differential operator. In this paper, we study properti...

    Óscar Ciaurri, Judit Mínguez Ceniceros in Revista de la Real Academia de Ciencias Ex… (2019)

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    Article

    Singular Measures and Convolution Operators

    We show that in the study of certain convolution operators, functions can be replaced by measures without changing the size of the constants appearing in weak type (1, 1) inequalities. As an application, we pr...

    J. M. Aldaz, Juan L. Varona in Acta Mathematica Sinica, English Series (2007)

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    Article

    Heat and Poisson Semigroups for Fourier-Neumann Expansions

    Given \(\alpha > -1,\) consider the second order differential operator in

    Jorge J. Betancor, Oscar Ciaurri, Teresa Martinez, Mario Perez in Semigroup Forum (2006)

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    Article

    Rational values of the arccosine function

    We give a short proof to characterize the cases when arccos(√r), the arccosine of the squareroot of a rational number r ∈ [0, 1], is a rational multiple of π: This happens exactly if r is an integer multiple of 1...

    Juan L. Varona in Central European Journal of Mathematics (2006)

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    Article

    Graphic and numerical comparison between iterative methods

    Juan L. Varona in The Mathematical Intelligencer (2002)

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    Article

    Fourier series of functions whose Hankel transform is supported on [0, 1]

    LetJ μ denote the Bessel function of order μ. For α>−1, the system x−α/2−1/2Jα+2n+1(x1/2, n=0, 1, 2,..., is orthogonal onL 2((0, ∞),x α dx). In this paper we study the mean con...

    Juan L. Varona in Constructive Approximation (1994)