3 papers
math.CA2025
Global Rational Approximations of Functions With Factorially Divergent Asymptotic Series
N. Castillo, O. Costin, R. D. Costin
We construct a new type of convergent, and asymptotic, representations, dyadic expansions. Their convergence is geometric and the region of convergence often extends from infinity…
math.CA2024
Long time evolution of the Hénon-Heiles system for small energy
Ovidiu Costin, Rodica Costin, Kriti Sehgal
The Hénon-Heiles system, initially introduced as a simplified model of galactic dynamics, has become a paradigmatic example in the study of nonlinear systems. Despite its simplici…
math.CA2024
Parabolic cylinder functions revisited using the Laplace transform
Rodica D. Costin, Georgios Mavrogiannis
In this paper we gather and extend classical results for parabolic cylinder functions, namely solutions of the Weber differential equations, using a systematic approach by Borel-La…