YES(O(1),O(n^1)) We are left with following problem, upon which TcT provides the certificate YES(O(1),O(n^1)). 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(O(1),O(n^1)) We use the processor 'Small Polynomial Path Order (PS,1-bounded)' to orient following rules strictly. 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) } The induced complexity on above rules (modulo remaining rules) is YES(?,O(n^1)) . These rules are moved into the corresponding weak component(s). Sub-proof: ---------- The input was oriented with the instance of 'Small Polynomial Path Order (PS,1-bounded)' as induced by the safe mapping safe(sum) = {}, safe(0) = {}, safe(s) = {1}, safe(+) = {1, 2}, safe(sqr) = {}, safe(*) = {1, 2} and precedence sum > sqr . Following symbols are considered recursive: {sum} The recursion depth is 1. 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) We return to the main proof. We are left with following problem, upon which TcT provides the certificate YES(O(1),O(1)). Weak 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(O(1),O(1)) Empty rules are trivially bounded Hurray, we answered YES(O(1),O(n^1))