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Asymptotic expansions for Moench's integral transform of hydrology
(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 ...
An asymptotic expansion of the hyberbolic umbilic catastrophe integral
(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 approximation of a highly oscillatory integral with application to the canonical catastrophe integrals
(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. ...
New recurrence relations for several classical families of polynomials
(Taylor and Francis, 2021)
info:eu-repo/semantics/article,
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 analytic representations of the hypergeometric functions p+1Fp
(Springer, 2021)
info:eu-repo/semantics/article,
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 ...
Uniform convergent expansions of integral transforms
(American Mathematical Society, 2021)
info:eu-repo/semantics/article,
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 ...
The swallowtail integral in the highly oscillatory region II
(Kent State UniversityJohann Radon Institute (RICAM), 2020)
info:eu-repo/semantics/article,
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
(Taylor & Francis, 2021)
info:eu-repo/semantics/article,
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 ...
The uniform asymptotic method "saddle point near an end point" revisited
(Elsevier, 2024)
Artículo / Artikulua,
We continue the program initiated in [López & all, 2009–2011] to simplify asymptotic methods for integrals: in this paper we revise the uniform method ‘‘saddle point near an end point’’. We obtain a more systematic version ...
Series representations of the Volterra function and the Fransén–Robinson constant
(Elsevier, 2021)
info:eu-repo/semantics/article,
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 ...