YES(O(1),O(n^2)) We are left with following problem, upon which TcT provides the certificate YES(O(1),O(n^2)). Strict Trs: { exp(x, 0()) -> s(0()) , exp(x, s(y)) -> *(x, exp(x, y)) , *(0(), y) -> 0() , *(s(x), y) -> +(y, *(x, y)) , -(x, 0()) -> x , -(0(), y) -> 0() , -(s(x), s(y)) -> -(x, y) } Obligation: innermost runtime complexity Answer: YES(O(1),O(n^2)) We use the processor 'Small Polynomial Path Order (PS,2-bounded)' to orient following rules strictly. Trs: { exp(x, 0()) -> s(0()) , exp(x, s(y)) -> *(x, exp(x, y)) , *(0(), y) -> 0() , *(s(x), y) -> +(y, *(x, y)) , -(x, 0()) -> x , -(0(), y) -> 0() , -(s(x), s(y)) -> -(x, y) } The induced complexity on above rules (modulo remaining rules) is YES(?,O(n^2)) . 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,2-bounded)' as induced by the safe mapping safe(exp) = {}, safe(0) = {}, safe(s) = {1}, safe(*) = {2}, safe(+) = {1, 2}, safe(-) = {2} and precedence exp > *, - > *, exp ~ - . Following symbols are considered recursive: {exp, *, -} The recursion depth is 2. For your convenience, here are the satisfied ordering constraints: exp(x, 0();) > s(; 0()) exp(x, s(; y);) > *(x; exp(x, y;)) *(0(); y) > 0() *(s(; x); y) > +(; y, *(x; y)) -(x; 0()) > x -(0(); y) > 0() -(s(; x); s(; y)) > -(x; y) 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: { exp(x, 0()) -> s(0()) , exp(x, s(y)) -> *(x, exp(x, y)) , *(0(), y) -> 0() , *(s(x), y) -> +(y, *(x, y)) , -(x, 0()) -> x , -(0(), y) -> 0() , -(s(x), s(y)) -> -(x, y) } Obligation: innermost runtime complexity Answer: YES(O(1),O(1)) Empty rules are trivially bounded Hurray, we answered YES(O(1),O(n^2))