Just a few set-sounding operations on lists. If you want sets, use the `Set' module.
unionLists :: Eq a => [a] -> [a] -> [a] intersectLists :: Eq a => [a] -> [a] -> [a] minusList :: Eq a => [a] -> [a] -> [a] disjointLists :: Eq a => [a] -> [a] -> Bool intersectingLists :: Eq a => [a] -> [a] -> Bool