Problemi al contorno con condizioni omogenee per le equazioni quasi-ellittiche.

We are concerned with non-variational boundary value problems, with omogeneus boundary conditions, for linear partial differential equations of quasi-elliptic type in a bounded domain Θ in R. It is well known that some of difficulties which arise in treating such problems, in comparison with « regular » elliptic problems, are connected with the presence of angular points in Θ: let us point out with B. Pini [32] that « a bounded domain for which it is possible to assign a correct boundary value problem for a quasi-elliptic but not elliptic equation always has angular points ». We suppose Θ is a cartesian product of a finite number of open sets and, in order to overcome the difficulties attached to the presence of angular points in Θ, taking as a model the two previous papers [33], [34] devoted to elliptic problems with singular data, we investigate the problem within suitable Sobolev weight spaces, connected with the angular points of Θ and included in the ones we have studied in [35]. Within such spaces we get existence and uniqueness theorems. [ABSTRACT FROM AUTHOR]