Cdr-cdr-induct
(cdr-cdr-induct x y) inducts by simultaneously cdr'ing
x and y until we reach the end of either.
Definitions and Theorems
Function: cdr-cdr-induct
(defun cdr-cdr-induct (x y)
(if (or (atom x) (atom y))
nil
(cdr-cdr-induct (cdr x) (cdr y))))