CO3L: Compact O3F Language

This paper presents CO3L, a compact, expressive and easy to use language for ontology representation. CO3L reflects the O3F model of ontology representation proposed elsewhere. The proposed language enables the representation of basic ontological entities, their relationships, and arbitrary axioms of the domain. Ontological entities include classes, properties, methods, facets and types. Relationships include n-ary associations and inheritance. Axioms may be used to capture complex constraints and relations between entities, to define relational and functional methods, and to represent the effects of the execution of action methods in the world. CO3L is based on the language of the first order logic, with explicit world states; the relational operator State/1, which is true of world state designators; the functional operator Do/2, which returns the world state designator resulting of the execution of an action in a given world state; and the modal operator Holds/2 which is true of propositions satisfied in given world states.