Now showing items 21-24 of 24

    • Uniform representation of the incomplete beta function in terms of elementary functions 

      Ferreira, Chelo; López García, José Luis Upna; Pérez Sinusía, Ester Upna (Kent State UniversityJohann Radon Institute (RICAM), 2018)   Artículo / Artikulua  OpenAccess
      We consider the incomplete beta function Bz(a, b) in the maximum domain of analyticity of its three variables: a, b, z ∈ C, −a /∈ N, z /∈ [1, ∞). For <b ≤ 1 we derive a convergent expansion of z−aBz(a, b) in terms of the ...
    • Uniformly convergent expansions for the generalized hypergeometric functions p –1Fp and pFp 

      López García, José Luis Upna; Pagola Martínez, Pedro Jesús Upna; Karp, D. B. (Taylor & Francis, 2020)   Artículo / Artikulua
      We derive a convergent expansion of the generalized hypergeometric function p−1 F p in terms of the Bessel functions 0 F 1 that holds uniformly with respect to the argument in any horizontal strip of the complex plane. We ...
    • The use of two-point Taylor expansions in singular one-dimensional boundary value problems I 

      Ferreira, Chelo; López García, José Luis Upna; Pérez Sinusía, Ester Upna (Elsevier, 2018)   Artículo / Artikulua  OpenAccess
      We consider the second-order linear differential equation (x + 1)y′′ + f(x)y′ + g(x)y = h(x) in the interval (−1, 1) with initial conditions or boundary conditions (Dirichlet, Neumann or mixed Dirichlet-Neumann). The ...
    • Zernike-like systems in polygons and polygonal facets 

      Ferreira, Chelo; López García, José Luis Upna; Navarro, Rafael; Pérez Sinusía, Ester Upna (Optical Society of America, 2015)   Artículo / Artikulua  OpenAccess
      Zernike polynomials are commonly used to represent the wavefront phase on circular optical apertures, since they form a complete and orthonormal basis on the unit disk. In [Diaz et all, 2014] we introduced a new Zernike ...