AGG gives us a possibility to enrich the type graph
with an inheritance relation between nodes.
Each node type can have one or more direct ancestor (parent) from which it
inherits the attributes and edges.
The parent node can be defined using item Set Parent of the
pop-up menu Operations of nodes. After selecting the parent
by clicking the left button on the appropriate node the inheritance edge appears.
Deletion inheritance relation is possible using item Unset Parent
and clicking the left button on the parent to delete.
It is also possible to define a node type as an abstract type by using item Abstract of the context pop-up menu [Operations. It is not allowed to create an instance node of an abstract type.
The multiplicity of a parent type also has an effect on the number of instances of successor types in a graph. Since all successor types can be seen as instances of that parent type, the sum of all instances of all child types is limited by the multiplicity set for the parent type. Similiar for edges inherited from a parent node, the overall number of incoming or outgoing edges is limited by the multiplicity set for the edge connected to the parent type.
Now it is possible to define abstract rules, containing ancestor nodes.