YES(?,O(n^1)) We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { g(c(x, s(y))) -> g(c(s(x), y)) , f(x) -> x , f(c(s(x), y)) -> f(c(x, s(y))) , f(f(x)) -> f(d(f(x))) } Obligation: innermost runtime complexity Answer: YES(?,O(n^1)) Arguments of following rules are not normal-forms: { f(f(x)) -> f(d(f(x))) } All above mentioned rules can be savely removed. We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { g(c(x, s(y))) -> g(c(s(x), y)) , f(x) -> x , f(c(s(x), y)) -> f(c(x, s(y))) } Obligation: innermost runtime complexity Answer: YES(?,O(n^1)) The problem is match-bounded by 1. The enriched problem is compatible with the following automaton. { g_0(2) -> 1 , g_0(3) -> 1 , g_0(5) -> 1 , g_1(6) -> 1 , c_0(2, 2) -> 2 , c_0(2, 2) -> 4 , c_0(2, 3) -> 2 , c_0(2, 3) -> 4 , c_0(2, 5) -> 2 , c_0(2, 5) -> 4 , c_0(3, 2) -> 2 , c_0(3, 2) -> 4 , c_0(3, 3) -> 2 , c_0(3, 3) -> 4 , c_0(3, 5) -> 2 , c_0(3, 5) -> 4 , c_0(5, 2) -> 2 , c_0(5, 2) -> 4 , c_0(5, 3) -> 2 , c_0(5, 3) -> 4 , c_0(5, 5) -> 2 , c_0(5, 5) -> 4 , c_1(2, 7) -> 4 , c_1(2, 7) -> 8 , c_1(3, 7) -> 4 , c_1(3, 7) -> 8 , c_1(5, 7) -> 4 , c_1(5, 7) -> 8 , c_1(7, 2) -> 6 , c_1(7, 3) -> 6 , c_1(7, 5) -> 6 , s_0(2) -> 3 , s_0(2) -> 4 , s_0(3) -> 3 , s_0(3) -> 4 , s_0(5) -> 3 , s_0(5) -> 4 , s_1(2) -> 7 , s_1(3) -> 7 , s_1(5) -> 7 , s_1(7) -> 7 , f_0(2) -> 4 , f_0(3) -> 4 , f_0(5) -> 4 , f_1(8) -> 4 , d_0(2) -> 4 , d_0(2) -> 5 , d_0(3) -> 4 , d_0(3) -> 5 , d_0(5) -> 4 , d_0(5) -> 5 , 2 -> 4 , 3 -> 4 , 5 -> 4 , 8 -> 4 } Hurray, we answered YES(?,O(n^1))