Existence results for a class of evolution equations of mixed type

We give an existence result for the evolution equation in the space where is a Banach space and is a non-invertible operator (the equation may be partially elliptic and partially parabolic, both forward and backward) and we study the “Cauchy-Dirichlet” problem associated to this equation (indeed also for the inclusion . We also investigate continuous and compact embeddings of and regularity in time of the solution. At the end we give some examples of different .