Class Axioms

Class Axioms are used to define classes, e.g in <owl:class/> defines the existence of a class and is a class axiom, likewise is the ID of the class a class axiom.

The set of individuals linked to the class is called class extension.

SubClassOf axioms

It means the class extension of a class is a subclass of another classes extension. So the set of individuals in the class 1 are a subset of the set of individuals of class 2.

Equivalent classes axioms

Equivalent class axioms link one class desciption to another class description, when these descriptions have the same class extension.

Disjoint classes axioms

These axioms ensure that a class extension with two class descriptions have no individuals in common.

Sources

1. https://www.w3.org/TR/owl-ref/