+
+
+-- | Returns 'True' if the lists xs and ys are disjoint, 'False'
+-- otherwise.
+--
+-- Examples:
+--
+-- >>> disjoint [1,2,3] [4,5,6]
+-- True
+--
+-- >>> disjoint [1,2,3] [3,4,5]
+-- False
+--
+disjoint :: (Eq a) => [a] -> [a] -> Bool
+disjoint xs ys =
+ intersect xs ys == []