% -*-Prolog-*-
:- expects_dialect(pfc).

% A company is a kind of business entity with at least one officer.  Known
% companies include XYZ_CORP and ABC_CORP.  All of a company's officers
% are people, subsidiaries of companies are themselves companies, and for
% any given company C and any given subsidiary S of C, C is an owner of S.
% 
% 	(define_prim_relation COMPANY (?c)
% 		(and (BUSINESS_ENTITY ?c) (at_least 1 (OFFICER ?c))))
% 	(COMPANY XYZ_CORP)
% 	(COMPANY ABC_CORP)
% 	(forall (COMPANY ?c)
% 		(and (all (OFFICER ?c) (PERSON))
% 		     (all (SUBSIDIARY ?c) (COMPANY))
% 		     (forall ?s (implies (SUBSIDIARY ?c ?s)
% 					 (OWNED_BY ?s ?c)))))  
% 

business_entity(C), officer(C,P) ==> company(C).

company(xyz_corp).
company(abc_corp).

company(C,) ==>
 (officer(C,P) ==> person(P)),
 (subsidiary(C,C2) ==> company(C), owned_by(C2,C)).