Mark44,
I think I am grasping this from this end.
So, let's see if I understand this.
(x,y) and (y,x) are-
(x,y) → ref
(y,z) → ref
Now this 'map to', 'corresponds to', or ' → ' then becomes (A,B), meaning the result of (x,y) → ? would be (x,y) → A and (y,z) → B, which then...