A local constancy principle for the solutions of certain overdetermined systems of first-order linear partial differential equations. (English) Zbl 0475.35027

Adv. Math., Suppl. Stud. 7A, 245-262 (1981).


35F05 Linear first-order PDEs
35A30 Geometric theory, characteristics, transformations in context of PDEs
32C05 Real-analytic manifolds, real-analytic spaces
65H10 Numerical computation of solutions to systems of equations