TRS:
 { sum(0()) -> 0(),
  sum(s(x)) -> +(sqr(s(x)), sum(x)),
     sqr(x) -> *(x, x),
  sum(s(x)) -> +(*(s(x), s(x)), sum(x))}
 Cdiprover:
  Interpretation class: pizerosimplemixed
  Complexity bound: POLYTIME COMPUTABLE
  *(X6, X5) = + 1*X5 + 1*X6 + 1
  s(X4) = + 1*X4 + 1
  sqr(X3) = + 0*X3^2 + 2 + 2*X3
  +(X2, X1) = + 1*X1 + 1*X2 + 1
  sum(X0) = + 3*X0^2 + 0 + 3*X0
  0 = + 1
  
  Qed