In this work we establish a local existence theory for the initial value problem associated to the general quasi-linear ultrahyperbolic Schr\"odinger equation.
@article{arxiv.math/0503206,
title = {The General Quasilinear Ultrahyperbolic Schr\"odinger Equation},
author = {C. E. Kenig and G. Ponce and C. Rolvung and L. Vega},
journal= {arXiv preprint arXiv:math/0503206},
year = {2007}
}