Entity modelling
From Wiki
At the level of entity modelling COM is based on the theory of partially ordered sets and most its main properties and mechanisms are based on ordering of elements. Within a partial order we distinguish between greater elements and lesser elements.
Any element in COM is viewed as a primitive thing without any intrinsic properties and all its semantic characteristics depend on how they are ordered. In other words, if elements of the model will be ordered in one way then it will have one meaning while if we change the ordering then the model will change its semantics.
Partial order among elements is established by means of references stored in elements. The fundamental assumption here is that a reference points to a greater element while this element is a lesser element in the partially ordered set.
