Some sharp null-form type estimates for the Klein--Gordon equation

Abstract

We establish a sharp bilinear estimate for the Klein-Gordon propagator in the spirit of recent work of Beltran-Vega. Our approach is inspired by work in the setting of the wave equation due to Bez, Jeavons and Ozawa. As a consequence of our main bilinear estimate, we deduce several sharp estimates of null-form type and recover some sharp Strichartz estimates found by Quilodrán and Jeavons.