On well-posedness for some Korteweg-De Vries type equations with variable coefficients

Luc Molinet (1) , Raafat Talhouk (2) , Ibtissame Zaiter (2)

1 IDP - Institut Denis Poisson
2 UL - Université Libanaise, Faculté des Sciences Section (1) Hadath-Beyrouth

In this paper, KdV-type equations with time-and space-dependent coefficients are considered. Assuming that the dispersion coefficient in front of u_{xxx} is positive and uniformly bounded away from the origin and that a primitive function of the ratio between the anti-dissipation and the dispersion coefficients is bounded from below, we prove the existence and uniqueness of a solution u such that hu belongs to a classical Sobolev space, where h is a function related to this ratio. The LWP in H^s (\R), s > 1/2, in the classical (Hadamard) sense is also proven under an assumption on the integrability of this ratio. Our approach combines a change of unknown with dispersive estimates. Note that previous results were restricted to H^s (\R), s > 3/2, and only used the dispersion to compensate the anti-dissipation and not to lower the Sobolev index required for well-posedness.

Mots clés: KdV; Variable coefficients; Well-posedness

Domaines: Equations aux dérivées partielles [math.AP]

Luc Molinet, Raafat Talhouk, Ibtissame Zaiter. On well-posedness for some Korteweg-De Vries type equations with variable coefficients. 2021. ⟨hal-03325490⟩