Listar INAMAT2 - Institute for Advanced Materials and Mathematics por autor UPNA "López García, José Luis"
Mostrando ítems 1-20 de 27
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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 ... -
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 and asymptotic methods for second-order difference equations with a large parameter
Ferreira González, Chelo; López García, José Luis ; Pérez Sinusía, Ester (Springer, 2018)
Artículo / Artikulua
We consider the second-order linear difference equation y(n+2)−2ay(n+1)−Λ2y(n)=g(n)y(n)+f(n)y(n+1) , where Λ is a large complex parameter, a≥0 and g and f are sequences of complex numbers. Two methods are proposed to find ... -
Convergent expansions of the Bessel functions in terms of elementary functions
López García, José Luis ; Pagola Martínez, Pedro Jesús (Springer US, 2018)
Artículo / Artikulua
We consider the Bessel functions Jν (z) and Yν (z) for ν > −1/2 and z ≥ 0. We derive a convergent expansion of Jν (z) in terms of the derivatives of (sin z)/z, and a convergent expansion of Yν (z) in terms of derivatives ... -
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); ... -
Convergent expansions of the incomplete gamma functions in terms of elementary functions
Bujanda Cirauqui, Blanca ; López García, José Luis ; Pagola Martínez, Pedro Jesús (World Scientific Publishing, 2017)
Artículo / Artikulua
We consider the incomplete gamma function γ(a,z) for Ra>0 and z∈C. We derive several convergent expansions of z−aγ(a,z) in terms of exponentials and rational functions of z that hold uniformly in z with Rz bounded from ... -
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 ... -
Effect of high-energy ball-milling on the magnetostructural properties of a Ni45Co5Mn35Sn15 alloy
López García, José Luis ; Sánchez-Alarcos Gómez, Vicente ; Recarte Callado, Vicente ; Rodríguez Velamazán, José Alberto; Unzueta, Iraultza; García, José Ángel; Plazaola, Fernando; La Roca, Paulo Matías ; Pérez de Landazábal Berganzo, José Ignacio (Elsevier, 2021)
Artículo / Artikulua
The effect of high-energy ball-milling on the magnetostructural properties of a Ni45Co5Mn35Sn15 alloy in austenitic phase at room temperature has been analyzed by neutron and high-resolution X-ray diffraction. The ball ... -
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 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 ... -
The Pearcey integral in the highly oscillatory region
López García, José Luis ; Pagola Martínez, Pedro Jesús (Elsevier, 2016)
Artículo / Artikulua
We consider the Pearcey integral P(x, y) for large values of |y| and bounded values of |x|. The integrand of the Pearcey integral oscillates wildly in this region and the asymptotic saddle point analysis is complicated. ... -
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 ... -
A simplification of the stationary phase method: application to the Anger and Weber functions
López García, José Luis (Kent State UniversityJohann Radon Institute (RICAM), 2017)
Artículo / Artikulua
The main difficulty in the practical use of the stationary phase method in asymptotic expansions of integrals is originated by a change of variables. The coefficients of the asymptotic expansion are the coefficients of the ... -
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 ...
