WORST_CASE(?,O(n^1)) Solution: --------- f :: [A(1)] -(0)-> A(0) g :: [A(1)] -(1)-> A(1) g :: [A(0)] -(0)-> A(0) Cost Free Signatures: --------------------- f :: [A_cf(0)] -(0)-> A_cf(0) g :: [A_cf(0)] -(0)-> A_cf(0)