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: { g(0()) -> 0() , g(s(x)) -> f(g(x)) , f(0()) -> 0() } 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: { g(0()) -> 0() , g(s(x)) -> f(g(x)) , f(0()) -> 0() } 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(g) = {}, safe(0) = {}, safe(s) = {1}, safe(f) = {1} and precedence g > f . Following symbols are considered recursive: {g} The recursion depth is 1. For your convenience, here are the satisfied ordering constraints: g(0();) > 0() g(s(; x);) > f(; g(x;)) f(; 0()) > 0() 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: { g(0()) -> 0() , g(s(x)) -> f(g(x)) , f(0()) -> 0() } Obligation: innermost runtime complexity Answer: YES(O(1),O(1)) Empty rules are trivially bounded Hurray, we answered YES(O(1),O(n^1))