M-Adhesive categories

[ggazzi]

Some categories have different classes of morphism, not just epi/mono/iso. In particular, some categories are adhesive with respect to a subclass N of monomorphisms. Some will further restrict the morphisms which are allowed in productions.

An example is Symbolic Graph Transformation, where rules must be monomorphic in the graph component and isomorphic in the attribute component.

These are not contemplated in the current architecture.

[ggazzi]

This should be addressed with issue #25