YES(?,O(n^1)) We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { active(f(x)) -> f(active(x)) , active(f(x)) -> mark(x) , f(mark(x)) -> mark(f(x)) , f(ok(x)) -> ok(f(x)) , f(found(x)) -> found(f(x)) , top(active(c())) -> top(mark(c())) , top(mark(x)) -> top(check(x)) , top(found(x)) -> top(active(x)) , check(x) -> start(match(f(X()), x)) , check(f(x)) -> f(check(x)) , start(ok(x)) -> found(x) , match(f(x), f(y)) -> f(match(x, y)) , match(X(), x) -> proper(x) , proper(f(x)) -> f(proper(x)) , proper(c()) -> ok(c()) } 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. { active_0(3) -> 1 , active_0(5) -> 1 , active_0(9) -> 1 , active_0(11) -> 1 , active_0(12) -> 1 , active_1(3) -> 14 , active_1(5) -> 14 , active_1(9) -> 14 , active_1(11) -> 14 , active_1(12) -> 14 , f_0(3) -> 2 , f_0(5) -> 2 , f_0(9) -> 2 , f_0(11) -> 2 , f_0(12) -> 2 , f_1(3) -> 13 , f_1(5) -> 13 , f_1(9) -> 13 , f_1(11) -> 13 , f_1(12) -> 13 , f_1(17) -> 16 , f_2(20) -> 19 , f_3(25) -> 24 , mark_0(3) -> 3 , mark_0(5) -> 3 , mark_0(9) -> 3 , mark_0(11) -> 3 , mark_0(12) -> 3 , mark_1(13) -> 2 , mark_1(13) -> 13 , mark_1(21) -> 14 , top_0(3) -> 4 , top_0(5) -> 4 , top_0(9) -> 4 , top_0(11) -> 4 , top_0(12) -> 4 , top_1(14) -> 4 , top_2(22) -> 4 , c_0() -> 5 , c_1() -> 21 , check_0(3) -> 6 , check_0(5) -> 6 , check_0(9) -> 6 , check_0(11) -> 6 , check_0(12) -> 6 , check_1(3) -> 14 , check_1(5) -> 14 , check_1(9) -> 14 , check_1(11) -> 14 , check_1(12) -> 14 , check_2(21) -> 22 , start_0(3) -> 7 , start_0(5) -> 7 , start_0(9) -> 7 , start_0(11) -> 7 , start_0(12) -> 7 , start_1(15) -> 6 , start_2(18) -> 14 , start_3(23) -> 22 , match_0(3, 3) -> 8 , match_0(3, 5) -> 8 , match_0(3, 9) -> 8 , match_0(3, 11) -> 8 , match_0(3, 12) -> 8 , match_0(5, 3) -> 8 , match_0(5, 5) -> 8 , match_0(5, 9) -> 8 , match_0(5, 11) -> 8 , match_0(5, 12) -> 8 , match_0(9, 3) -> 8 , match_0(9, 5) -> 8 , match_0(9, 9) -> 8 , match_0(9, 11) -> 8 , match_0(9, 12) -> 8 , match_0(11, 3) -> 8 , match_0(11, 5) -> 8 , match_0(11, 9) -> 8 , match_0(11, 11) -> 8 , match_0(11, 12) -> 8 , match_0(12, 3) -> 8 , match_0(12, 5) -> 8 , match_0(12, 9) -> 8 , match_0(12, 11) -> 8 , match_0(12, 12) -> 8 , match_1(16, 3) -> 15 , match_1(16, 5) -> 15 , match_1(16, 9) -> 15 , match_1(16, 11) -> 15 , match_1(16, 12) -> 15 , match_2(19, 3) -> 18 , match_2(19, 5) -> 18 , match_2(19, 9) -> 18 , match_2(19, 11) -> 18 , match_2(19, 12) -> 18 , match_3(24, 21) -> 23 , X_0() -> 9 , X_1() -> 17 , X_2() -> 20 , X_3() -> 25 , proper_0(3) -> 10 , proper_0(5) -> 10 , proper_0(9) -> 10 , proper_0(11) -> 10 , proper_0(12) -> 10 , proper_1(3) -> 8 , proper_1(5) -> 8 , proper_1(9) -> 8 , proper_1(11) -> 8 , proper_1(12) -> 8 , ok_0(3) -> 11 , ok_0(5) -> 11 , ok_0(9) -> 11 , ok_0(11) -> 11 , ok_0(12) -> 11 , ok_1(13) -> 2 , ok_1(13) -> 13 , ok_1(21) -> 8 , ok_1(21) -> 10 , found_0(3) -> 12 , found_0(5) -> 12 , found_0(9) -> 12 , found_0(11) -> 12 , found_0(12) -> 12 , found_1(3) -> 7 , found_1(5) -> 7 , found_1(9) -> 7 , found_1(11) -> 7 , found_1(12) -> 7 , found_1(13) -> 2 , found_1(13) -> 13 } Hurray, we answered YES(?,O(n^1))