YES(?,O(n^1)) We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { a__f(X) -> f(X) , a__f(f(a())) -> a__f(g(f(a()))) , mark(f(X)) -> a__f(mark(X)) , mark(a()) -> a() , mark(g(X)) -> g(X) } Obligation: runtime complexity Answer: YES(?,O(n^1)) The input is overlay and right-linear. Switching to innermost rewriting. We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { a__f(X) -> f(X) , a__f(f(a())) -> a__f(g(f(a()))) , mark(f(X)) -> a__f(mark(X)) , mark(a()) -> a() , mark(g(X)) -> g(X) } Obligation: innermost runtime complexity Answer: YES(?,O(n^1)) The problem is match-bounded by 3. The enriched problem is compatible with the following automaton. { a__f_0(2) -> 1 , a__f_0(3) -> 1 , a__f_0(4) -> 1 , a__f_1(6) -> 1 , a__f_1(9) -> 5 , a__f_1(9) -> 9 , a__f_2(10) -> 5 , a__f_2(10) -> 9 , f_0(2) -> 2 , f_0(3) -> 2 , f_0(4) -> 2 , f_1(2) -> 1 , f_1(3) -> 1 , f_1(4) -> 1 , f_1(8) -> 7 , f_2(6) -> 1 , f_2(9) -> 5 , f_2(9) -> 9 , f_2(12) -> 11 , f_3(10) -> 5 , f_3(10) -> 9 , a_0() -> 3 , a_1() -> 5 , a_1() -> 8 , a_1() -> 9 , a_2() -> 12 , g_0(2) -> 4 , g_0(3) -> 4 , g_0(4) -> 4 , g_1(2) -> 5 , g_1(2) -> 9 , g_1(3) -> 5 , g_1(3) -> 9 , g_1(4) -> 5 , g_1(4) -> 9 , g_1(7) -> 6 , g_2(11) -> 10 , mark_0(2) -> 5 , mark_0(3) -> 5 , mark_0(4) -> 5 , mark_1(2) -> 9 , mark_1(3) -> 9 , mark_1(4) -> 9 } Hurray, we answered YES(?,O(n^1))