On the regularity of solutions to the $k$-generalized Korteweg-de Vries equation

This work is concerned with special regularity properties of solutions to the $k$-generalized Korteweg-de Vries equation. In cite{IsazaLinaresPonce} it was established that if the initial datun $u_0in H^l((b,infty))$ for some $linmathbb Z^+$ and $bin mathbb R$, then the corresponding solution $u(cdot,t)$ belongs to $H^l((beta,infty))$ for any $beta in mathbb R$ and any $tin (0,T)$. Our goal here is to extend this result to the case where $,lin mathbb R^+$.