Korovkin type approximation closures for vector-valued functions

Korovkin type approximation closures are discussed in the spaces of vector-valued functions on compact Hausdorff spaces. For this, it is introduced that the notions of an M_T-envelope, an M_T-affine function as well as an M_T-representing operator and a T-Choquet boundary for a linear subspace M and a positive linear operator T under certain appropriate requirements