On Huygens’ Principle for the Hodge-de Rham Equations with Lorentzian Gauge

Abstract

In an arbitrary curved space-time the Hodge-de Rham equations with Lorentzian gauge are studied. Using the spinor calculus and propositions on the curvature tensors, espe-cially on Hall’s canonical forms of Ricci tensors, some properties of the tail terms with respect to second order differential operators are proved. Finally, all Huygens’ operators are explicitly determined.