I-Maps and D-Maps

If a graph is an I-Map for a set of independencies then it will still be an I-Map if we add extra edges
- In particular the complete graph on a set of vertices is trivially always an I-Map
Likewise if a graph is a D-Map for a set of dependencies then a graph containing fewer edges will also be a D-Map
- A graph containing no edges will (trivially) be a D-Map