Sunao Ouchi

activity

20222026

collaborators

3 papers

math.CA2026

Another approach to WKB analysis

Sunao Ouchi

A singular perturbation problem called WKB equation (Eq) $h^{2} u (x, h) - Q (x) u (x, h) = 0$ is studied. $h > 0$ is a small parameter. Investigation of (Eq) has long history. Recently it has de…

math.AP2024

Cauchy problem in function spaces with asymptotic expansions with respect to time variable

Sunao Ouchi

A system of nonlinear Cauchy problem $\partial_{t} u_{i} = f_{i} (t, x, U, \nabla_{x} U)$ $u_{i} (0, x) = u_{i, 0} (x)$ is studied in function spaces with asymptotic expansion with respect to $t$ . To…

math.CA2022

Construction of solutions of nonlinear irregular singular differential equations by Borel summable functions and an application to Painlevé equations

Sunao Ouchi

A system of nonlinear differential equations $x^{1 + γ} \frac{d Y}{d x} = F_{0} (x) + A (x) Y + F (x, Y)$ is considered. We study more precisely the meaning of asymptotic expansion of transformatio…