Symmetric hyperbolic Schr\"{o}dinger equations on tori

In this paper, we study the symmetric hyperbolic Schr"{o}dinger equations in the periodic setting. First, we prove full range Strichartz estimates on general tori by adapting Bourgain’s major arc method. The result is sharp for rational tori. Second, on two-dimensional rational tori, we establish optimal local well-posedness for two hyperbolic nonlinear Schr"{o}dinger (HNLS) equations: the septic HNLS and the hyperbolic-elliptic Davey-Stewartson system.