divisible n m = (mod m n)==0 
-- predicato vero sse m e' divisibile per n


divisiblebyboth n m x = (divisible n x)&&(divisible m x)


commonmultiples n m = numsatP (divisiblebyboth n m)


mcm n m = head (commonmultiples n m)  



-- Altra possibile implementazione:

firstcommon (x:xs) (y:ys) | x<y = firstcommon xs (y:ys)
                          | x>y = firstcommon (x:xs) ys
                          | otherwise = x


allmultiple n  = numsatP (divisible n)


mcm2 n m = firstcommon (allmultiple n) (allmultiple m)