Documentation

https://en.m.wikipedia.org/wiki/OntoClean

Rigidity: Rigid, Anti-Rigid and Semi-Rigid types (UFO-C on OntoUML)

N. Guarino/C. A. Welty, « An Overview of OntoClean », in Steffen Staab, ed., Handbook on ontologies, 2nd ed. Berlin: Springer, 2009.

Principes

* Rigidity (time-indexed qualities or classifications)

Essential properties define an entity throughout its life

A ‘student’ : not a class but a time-indexed property of a person

* Identity (terms and classes)

map vs a sketch vs an information object of type ‘map’ or ‘sketch’

* Unity (parthood)

A crowd of humans vs a group having a plan

* Dependence (one instance implies the existence of another one)

No human without a brain, no human without a birth