tween variables, and then we search the code for list insertions where the inserted element does not appear in the collection of associations (at least he is what I do! :-)).So, for example, if we have 3 lists A, B and C, and B was a member of A and C was a member of B, then we could see that it would be illegal to insert A into C, due to the following associations: A -> B -> C -> A.Again, the is