Hyperbolic Differential Operators and Related Problems

Аннотация

The papers collected in this volume are concerned with hyperbolic problems, or problems the methods of which are related to hyperbolic techniques. T. NISHITANI introduces a notion of nondegenerate characteristic for systems of linear partial differential equations of general order. He shows that nondegenerate characteristics are stable under hyperbolic perturbations, and he proves that if the coefficients of the system are real analytic and all characteristics are nondegenerate then the Cauchy problem for the system is well posed in the class of smooth functions.