YES(?,O(n^1)) We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { f(c(X, s(Y))) -> f(c(s(X), Y)) , g(c(s(X), Y)) -> f(c(X, s(Y))) } Obligation: innermost runtime complexity Answer: YES(?,O(n^1)) The problem is match-bounded by 2. The enriched problem is compatible with the following automaton. { f_0(2) -> 1 , f_0(3) -> 1 , f_1(5) -> 1 , f_1(7) -> 4 , f_2(8) -> 4 , c_0(2, 2) -> 2 , c_0(2, 3) -> 2 , c_0(3, 2) -> 2 , c_0(3, 3) -> 2 , c_1(2, 6) -> 7 , c_1(3, 6) -> 7 , c_1(6, 2) -> 5 , c_1(6, 3) -> 5 , c_1(10, 2) -> 7 , c_1(10, 3) -> 7 , c_2(9, 2) -> 8 , c_2(9, 3) -> 8 , c_2(9, 6) -> 8 , s_0(2) -> 3 , s_0(3) -> 3 , s_1(2) -> 6 , s_1(3) -> 6 , s_1(6) -> 6 , s_1(9) -> 10 , s_1(10) -> 10 , s_2(2) -> 9 , s_2(3) -> 9 , s_2(9) -> 9 , g_0(2) -> 4 , g_0(3) -> 4 } Hurray, we answered YES(?,O(n^1))