Codice 624-P Titolo On closed boundary value problems for equations of mixed elliptic-hyperbolic type Data 2005-02-01 Autore/i Lupo, Daniela ; Morawetz, Cathleen S. ; Payne, Kevin R. Link Download full text Abstract For partial differential equations of mixed elliptic-hyperbolic type we prove results on existence and existence with uniqueness of weak solutions for closed boundary value problems of Dirichlet and mixed Dirichlet-conormal types. These problems are of interest for applications to transonic flow and are over-determined for solutions with classical regularity. The method employed consists in variants of the a - b - c integral method of Friedrichs in Sobolev spaces with suitable weights. Particular attention is paid to the problem of attaining results with a minimum of restrictions on boundary geometry and the form of the type change function.