Complex-valued solutions of the mKdV equations in generalized Fourier-Lebesgue spaces

TL;DR

This paper investigates complex-valued solutions to the mKdV equation using generalized Fourier-Lebesgue spaces, establishing sharp local well-posedness results for low-regularity initial data.

Contribution

It introduces a unified Fourier-Lebesgue space framework and proves improved local well-posedness results for the mKdV equation.

Findings

Established sharp local well-posedness in generalized Fourier-Lebesgue spaces.

Unified modulation and Fourier-Lebesgue spaces for low-regularity analysis.

Improved previous results on mKdV solutions.

Abstract

We study the \emph{complex-valued} solutions to the Cauchy problem of the modified Korteweg-de Vries equation on the real line. To study the low-regularity problems, we employ a generalized Fourier-Lebesgue space $\widehat{M}^{s}_{r,q}(\mathbb{R})$ that unifies the modulation spaces and the Fourier-Lebesgue spaces. We then prove sharp local well-posedness results in this space by perturbation arguments using $X^{s,b}$-type spaces. Our results improve the previous one in \cite{GV}.