An equivalent formulation for variational problems with constraints

Abstract

The main purpose of this paper is to reconsider the studying of existence, uniqueness and approximation of solution to a variational problem with constraints. Under certain assumptions on the bilinear forms involved it is proved that the original formulation is equivalent to a simplified version of it on smaller spaces. By applying the usual Brezzi's theory to this new formulation a modified Babuska-Brezzi condition is deduced.