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The Expansion of ENDP in the Induction Step (Step 0)

The Expansion of ENDP in the Induction Step (Step 0)

Subgoal *1/2 
(IMPLIES (AND (NOT (ENDP 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)))). 

Click on the link above (the open parenthesis before ENDP) to replace (ENDP A) by its definition.