(+) :: Peano -> Peano -> Peano
-- testing 6 combinations of argument values
-- pruning with 0/0 rules
-- 3 candidates of size 1
-- 3 candidates of size 2
-- 3 candidates of size 3
-- 13 candidates of size 4
-- 19 candidates of size 5
-- tested 26 candidates
p + Z  =  p
p + S q  =  S (p + q)

(*) :: Peano -> Peano -> Peano
-- testing 7 combinations of argument values
-- pruning with 6/10 rules
-- 3 candidates of size 1
-- 3 candidates of size 2
-- 6 candidates of size 3
-- 6 candidates of size 4
-- 25 candidates of size 5
-- 63 candidates of size 6
-- tested 56 candidates
p * Z  =  Z
p * S q  =  p + p * q

