(<=> (Many-To-Many-Relation ?R) (And (Binary-Relation ?R) (Not (Function ?R)) (Not (Function (Inverse ?R)))))
(Not (Function (Inverse ?R))) (Not (Function ?R)) (Binary-Relation ?R)
(<=> (Many-To-Many-Relation ?R) (And (Binary-Relation ?R) (Not (Function ?R)) (Not (Function (Inverse ?R)))))