Listar Artículos de revista DEIM - EIMS Aldizkari artikuluak por autor UPNA "López García, José Luis"
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Analysis of singular one-dimensional linear boundary value problems using two-point Taylor expansions
Ferreira González, Chelo
; López García, José Luis 
; Pérez Sinusía, Ester (University of Szeged (Hungría), 2020)
Artículo / Artikulua 
We consider the second-order linear differential equation (x2 − 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 ... -
An analytic representation of the second symmetric standard elliptic integral in terms of elementary functions
Bujanda Cirauqui, Blanca ; López García, José Luis ; Pagola Martínez, Pedro Jesús ; Palacios Herrero, Pablo (Springer, 2022)
Artículo / Artikulua
We derive new convergent expansions of the symmetric standard elliptic integral RD(x,y,z), for x,y,z∈C∖(−∞,0], in terms of elementary functions. The expansions hold uniformly for large and small values of one of the three ... -
Analytical ray transfer matrix for the crystalline lens
Navarro, Rafael; Lockett-Ruiz, Verónica; López García, José Luis (OSA Publishing, 2022)
Artículo / Artikulua
We present the formulation of a paraxial ray transfer or ABCD matrix for onion-type GRIN lenses. In GRIN lenses, each iso-indicial surface (IIS) can be considered a refracting optical surface. If each IIS is a shell or ... -
Asymptotic approximation of a highly oscillatory integral with application to the canonical catastrophe integrals
Ferreira González, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Wiley, 2023)
Artículo / Artikulua
We consider the highly oscillatory integral 𝐹(𝑤) ∶= ∫ ∞ −∞ 𝑒𝑖𝑤(𝑡𝐾+2+𝑒𝑖𝜃𝑡𝑝) 𝑔(𝑡)𝑑𝑡 for large positive values of 𝑤, −𝜋 < 𝜃 ≤ 𝜋, 𝐾 and 𝑝 positive integers with 1 ≤ 𝑝 ≤ 𝐾, and 𝑔(𝑡) an entire function. ... -
An asymptotic expansion of the hyberbolic umbilic catastrophe integral
Ferreira González, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Springer, 2022)
Artículo / Artikulua
We obtain an asymptotic expansion of the hyperbolic umbilic catastrophe integral Ψ(H) (x,y,z) := ∫∞−∞∫∞−∞exp(i(s3+t3+zst +yt+xs))ds dt for large values of |x| and bounded values of |y| and |z|. The expansion is given ... -
Asymptotic expansions for Moench's integral transform of hydrology
López García, José Luis ; Pagola Martínez, Pedro Jesús ; Pérez Sinusía, Ester (MDPI, 2023)
Artículo / Artikulua
Theis' theory (1935), later improved by Hantush & Jacob (1955) and Moench (1971), is a technique designed to study the water level in aquifers. The key formula in this theory is a certain integral transform H[g](r,t) of ... -
A convergent and asymptotic Laplace method for integrals
López García, José Luis ; Pagola Martínez, Pedro Jesús ; Palacios Herrero, Pablo (Elsevier, 2023)
Artículo / Artikulua
Watson’s lemma and Laplace’s method provide asymptotic expansions of Laplace integrals F (z) := ∫ ∞ 0 e −zf (t) g(t)dt for large values of the parameter z. They are useful tools in the asymptotic approximation of ... -
Convergent expansions of the confluent hypergeometric functions in terms of elementary functions
Bujanda Cirauqui, Blanca ; López García, José Luis ; Pagola Martínez, Pedro Jesús (American Mathematical Society, 2018)
Artículo / Artikulua
We consider the confluent hypergeometric function M(a, b; z) for z ∈ C and Rb >Ra > 0, and the confluent hypergeometric function U(a, b; z) for b ∈ C, Ra > 0, and Rz > 0. We derive two convergent expansions of M(a, b; z); ... -
A convergent version of Watson’s lemma for double integrals
Ferreira González, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Taylor & Francis, 2022)
Artículo / Artikulua
A modification of Watson’s lemma for Laplace transforms ∞ 0 f(t) e−zt dt was introduced in [Nielsen, 1906], deriving a new asymptotic expansion for large |z| with the extra property of being convergent as well. Inspired ... -
New analytic representations of the hypergeometric functions p+1Fp
López García, José Luis ; Palacios Herrero, Pablo ; Pagola Martínez, Pedro Jesús (Springer, 2021)
Artículo / Artikulua
The power series expansions of the hypergeometric functions p+1Fp (a,b1,…,bp;c1,…,cp;z) converge either inside the unit disk |z|<1 or outside this disk |z|>1. Nørlund’s expansion in powers of z/(z−1) converges in the ... -
New recurrence relations for several classical families of polynomials
Ferreira González, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Taylor and Francis, 2021)
Artículo / Artikulua
In this paper, we derive new recurrence relations for the following families of polynomials: nörlund polynomials, generalized Bernoulli polynomials, generalized Euler polynomials, Bernoulli polynomials of the second kind, ... -
New series expansions for the ℋ-function of communication theory
Ferreira, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Taylor & Francis, 2023)
Artículo / Artikulua
TheH-function of communication theory plays an important role inthe error rate analysis in digital communication with the presenceof additive white Gaussian noise (AWGN) and generalized multipathfading conditions. In this ... -
On a particular class of Meijer's G functions appearing in fractional calculus
Karp, D. B.; López García, José Luis (Academic Publications, 2018)
Artículo / Artikulua
In this paper we investigate the Meijer G-function G p+1,p+1 p,1 which, for certain parameter values, represents the Riemann-Liouville fractional integral of the Meijer-Nørlund function G p,p. p,0 The properties of this ... -
Series representations of the Volterra function and the Fransén–Robinson constant
López García, José Luis ; Pagola Martínez, Pedro Jesús ; Palacios Herrero, Pablo (Elsevier, 2021)
Artículo / Artikulua
The Volterra function μ(t,β,α) was introduced by Vito Volterra in 1916 as the solution to certain integral equations with a logarithmic kernel. Despite the large number of applications of the Volterra function, the only ... -
The swallowtail integral in the highly oscillatory region II
Ferreira González, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Kent State UniversityJohann Radon Institute (RICAM), 2020)
Artículo / Artikulua
We analyze the asymptotic behavior of the swallowtail integral R ∞ −∞ e i(t 5+xt3+yt2+zt)dt for large values of |y| and bounded values of |x| and |z|. We use the simpli ed saddle point method introduced in [López et al., ... -
The swallowtail integral in the highly oscillatory region III
Ferreira González, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Taylor & Francis, 2021)
Artículo / Artikulua
We consider the swallowtail integral Ψ(x,y,z):=∫∞−∞ei(t5+xt3+yt2+zt)dt for large values of |z| and bounded values of |x| and |y|. The integrand of the swallowtail integral oscillates wildly in this region and the asymptotic ... -
Uniform approximations of the first symmetric elliptic integral in terms of elementary functions
Bujanda Cirauqui, Blanca ; López García, José Luis ; Pagola Martínez, Pedro Jesús ; Palacios Herrero, Pablo (Springer, 2022)
Artículo / Artikulua
We consider the standard symmetric elliptic integral RF(x, y, z) for complex x, y, z. We derive convergent expansions of RF(x, y, z) in terms of elementary functions that hold uniformly for one of the three variables x, y ... -
Uniform convergent expansions of integral transforms
López García, José Luis ; Palacios Herrero, Pablo ; Pagola Martínez, Pedro Jesús (American Mathematical Society, 2021)
Artículo / Artikulua
Several convergent expansions are available for most of the special functions of the mathematical physics, as well as some asymptotic expansions [NIST Handbook of Mathematical Functions, 2010]. Usually, both type of ... -
Uniform convergent expansions of the error function in terms of elementary functions
Ferreira González, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Springer, 2023)
Artículo / Artikulua
We derive a new analytic representation of the error function erfz in the form of a convergent series whose terms are exponential and rational functions. The expansion holds uniformly in z in the double sector | arg (±z) ... -
Uniformly convergent expansions for the generalized hypergeometric functions p –1Fp and pFp
López García, José Luis ; Pagola Martínez, Pedro Jesús ; 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 ...
