Editing Hierarchy (section)

==Informal representation==
In plain English, a hierarchy can be thought of as a [[Set (mathematics)|set]] in which:<ref name="Dawkins">{{cite conference|last=Dawkins|first=Richard|author-link=Richard Dawkins|title=Hierarchical organization: a candidate principle for ethology|conference=Growing points in ethology: based on a conference sponsored by St. John's College and King's College, Cambridge|editor1=Bateson, Paul Patrick Gordon |editor2=Hinde, Robert A.|year=1976|publisher=Cambridge University Press|location=Cambridge, England|isbn=0-521-29086-4|pages=7–54}}</ref>
# No element is superior to itself, and
# One element, the (''apex'' or ''hierarch''), is superior to all of the other elements in the set.
The first requirement is also interpreted to mean that a hierarchy can have no [[Cycle (graph theory)|circular relationships]]; the association between two objects is always [[Transitive relation|transitive]].
The second requirement asserts that a hierarchy must have a leader or [[root node|root]] that is common to all of the objects.