(Exists (?Y) (And (Integer ?Y) (Integer (* ?X ?Y))))
(<=> (Rational-Number ?X)
(And (Real-Number ?X)
(Exists (?Y) (And (Integer ?Y) (Integer (* ?X ?Y))))))
(<=> (Natural ?X) (And (Integer ?X) (> ?X 0)))
(=> (Floor $X $Y) (Integer $Y))
(=> (Integer-Decode-Float $X $Y) (Integer $Y))
(=> (Round $X $Y) (Integer $Y))