A note on the Ostrovsky equation in weighted Sobolev spaces

Abstract: In this work we consider the initial value problem (IVP) associated to the Ostrovsky equations $$\left. \begin{array}{rl} u_t+\partial_x^3 u\pm \partial_x^{-1}u +u \partial_x u &\hspace{-2mm}=0,\qquad\qquad x\in\mathbb R,\; t\in\mathbb R,\ u(x,0)&\hspace{-2mm}=u_0(x). \end{array} \right}$$ We study the well-posedness of the IVP in the weighted Sobolev spaces $$Z_{s,\frac{s}2}:={u\in H^s(\mathbb R):D_x^{-s} u\in L^2(\mathbb R)}\cap L^2(|x|^s dx ),$$ with $\frac34<s\leq 1$.