A Relationship between a Relational Sentence ?Relsent and a list ?Rs whereby
1. - ?Rs is a list of relation or function constants.
--and--
2. the R in ?Relsent is an item in the list ?Rs
(<=> (Restricted-Relsent ?Relsent ?Rs)
(And (Relsent ?Relsent)
(Forall (?R)
(=> (Item ?R ?Rs) (Or (Relconst ?R) (Funconst ?R))))
(Exists (?R ?Args)
(And (Item ?R ?Rs) (= ?Relsent (Cons ?R ?Args))))))
(<=> (Restricted-List-Of-Relsents ?List ?Rs)
(And (List ?List)
(Or (And (Relsent ?List) (Restricted-Relsent ?List ?Rs))
(And (Forall (?Relsent)
(=> (Item ?Relsent ?List)
(Restricted-Relsent ?Relsent ?Rs)))
(>= (Length ?List) 1)))))