Periodic Cubic Hyperbolic Schrödinger equation on $\T^2$
arXiv:1205.5205
Abstract
We consider the cubic Hyperbolic Schrödinger equation \eqref{eq:nls} on torus $\T^2$. We prove that sharp Strichartz estimate, which implies that \eqref{eq:nls} is analytic locally well-posed in in $H^s(\T^2)$ with , meanwhile, the ill-posedness in $H^s(\T^2)$ for is also obtained. The main difficulty comes from estimating the number of representations of an integer as a difference of squares.
The reference [6] is added according to Professor Tzvetkov, we also noticed that [8] generalized our main estimates by a different approach recently