Abstract
This paper considers a general framework for the study of the existence of
quasi-variational and variational solutions to a class of nonlinear evolution
systems in convex sets of Banach spaces describing constraints on a
linear combination of partial derivatives of the solutions. The quasi-linear operators are
of monotone type, but are not required to be coercive for the existence of weak solutions, which
is obtained by a double penalization/regularization for the approximation of the solutions. In
the case of time-dependent convex sets that are independent of the solution, we show
also the uniqueness and the continuous dependence of the strong solutions of the variational
inequalities, extending previous results to a more general framework.