This graph has three important properties:
1. Each point of the graph has an arrow looping around from it back to itself.
2. In each case where there is an arrow going from one point to a second, there is an
arrow going from the second point back to the first.
3. In each case where there is an arrow going from one point to a second and from the
second point to a third, there is an arrow going from the first point to the third. That
is, there are no “incomplete directed triangles” in the graph.
Properties (1), (2), and (3) correspond to properties of general relations called reflexivity,
symmetry, and transitivity.