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)))))