YES(?,POLY) We are left with following problem, upon which TcT provides the certificate YES(?,POLY). Strict Trs: { sum(0()) -> 0() , sum(s(x)) -> +(sqr(s(x)), sum(x)) , sum(s(x)) -> +(*(s(x), s(x)), sum(x)) , sqr(x) -> *(x, x) } Obligation: innermost runtime complexity Answer: YES(?,POLY) The input was oriented with the instance of 'Polynomial Path Order' as induced by the safe mapping safe(sum) = {}, safe(0) = {}, safe(s) = {1}, safe(+) = {1, 2}, safe(sqr) = {1}, safe(*) = {1, 2} and precedence sum > sqr . Following symbols are considered recursive: {sum, sqr} The recursion depth is 2. For your convenience, here are the satisfied ordering constraints: sum(0();) > 0() sum(s(; x);) > +(; sqr(; s(; x)), sum(x;)) sum(s(; x);) > +(; *(; s(; x), s(; x)), sum(x;)) sqr(; x) > *(; x, x) Hurray, we answered YES(?,POLY)