Theorem about pair equality in renamings.
Two pairs in a renaming are equal if and only if their cars or their cdrs are equal. This is because there cannot be two distinct pairs with the same car or cdr.
Theorem:
(defthm renaming-pair-equality (implies (and (member-equal pair1 (renaming->list ren)) (member-equal pair2 (renaming->list ren))) (equal (equal pair1 pair2) (or (equal (car pair1) (car pair2)) (equal (cdr pair1) (cdr pair2))))))