A Cyc taxonomic predicate (q.v.) that relates things of any kind to collections (see type of thing) of which they are instances. (Isa THING COL) means that THING is an instance of the collection COL. Isa is by far the most commonly-occurring predicate in the Cyc Knowledge Base, and is one of the relations most fundamental to the Cyc ontology. An important logical feature of Isa is that it transfers through generalization (q.v.): (Isa THING COL) and (generalization COL SUPERCOL) jointly imply (Isa THING SUPERCOL). This logical feature is expressed in a rule that -- along with various other rules that also sanction the derivation of Isa sentences -- has been asserted to the Knowledge Base. As a result, only a small fraction of the Isa based ground atomic formulas (or GAF s; see CycL closed atomic sentence) the Cyc system knows to be true have been manually asserted; the vast majority have been derived, or are derivable, automatically by the Cyc inference engine via the use of such rules. See also Element Of.
(Isa THING COL)means thatTHINGis an instance of the collectionCOL. Isa is by far the most commonly-occurring predicate in the Cyc Knowledge Base, and is one of the relations most fundamental to the Cyc ontology. An important logical feature of Isa is that it transfers through generalization (q.v.):(Isa THING COL)and(generalization COL SUPERCOL)jointly imply(Isa THING SUPERCOL). This logical feature is expressed in a rule that -- along with various other rules that also sanction the derivation of Isa sentences -- has been asserted to the Knowledge Base. As a result, only a small fraction of the Isa based ground atomic formulas (or GAF s; see CycL closed atomic sentence) the Cyc system knows to be true have been manually asserted; the vast majority have been derived, or are derivable, automatically by the Cyc inference engine via the use of such rules. See also Element Of.