Buscar
Mostrando ítems 1-10 de 21
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. ...
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 ...
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, ...
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 ...
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 ...
An analytic representation of the second symmetric standard elliptic integral in terms of elementary functions
(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 ...
A convergent version of Watson’s lemma for double integrals
(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 ...