Subgoal *1/2'
(IMPLIES (AND (CONSP A)
(EQUAL (APP (APP (CDR A) B) C)
(APP (CDR A) (APP B C))))
(EQUAL (APP (APP A B) C)
(APP A (APP B C)))).

Note that this is Subgoal *1/2'.
You may click here to return to the main proof.