\(C^{\infty }\) Well-Posedness of Higher Order Hyperbolic Pseudo-Differential Equations with Multiplicities
摘要
In this paper, we study higher order hyperbolic pseudo-differential equations with variable multiplicities. We work in arbitrary space dimension and we assume that the principal part is time-dependent only. We identify sufficient conditions on the roots and the lower order terms (Levi conditions) under which the corresponding Cauchy problem is