ldiff :: Triples -> Triples -> Triples
ldiff l1 l2 = Set.toList $(Set.fromList l1) `Set.difference` (Set.fromList l2)
ldiff :: Triples -> Triples -> Triples
ldiff l1 l2 = Set.toList $(Set.fromList l1) `Set.difference` (Set.fromList l2)
ldiff l1 l2 = Set.toList $(Set.fromList l1) `Set.difference` (Set.fromList l2)