YES(?,O(n^1)) We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { active(g(X)) -> mark(h(X)) , active(h(d())) -> mark(g(c())) , active(c()) -> mark(d()) , g(ok(X)) -> ok(g(X)) , h(ok(X)) -> ok(h(X)) , proper(g(X)) -> g(proper(X)) , proper(h(X)) -> h(proper(X)) , proper(c()) -> ok(c()) , proper(d()) -> ok(d()) , top(mark(X)) -> top(proper(X)) , top(ok(X)) -> top(active(X)) } Obligation: innermost runtime complexity Answer: YES(?,O(n^1)) The problem is match-bounded by 4. The enriched problem is compatible with the following automaton. { active_0(3) -> 1 , active_0(5) -> 1 , active_0(6) -> 1 , active_0(8) -> 1 , active_1(3) -> 14 , active_1(5) -> 14 , active_1(6) -> 14 , active_1(8) -> 14 , active_2(10) -> 15 , active_2(13) -> 15 , active_3(16) -> 17 , active_4(18) -> 19 , g_0(3) -> 2 , g_0(5) -> 2 , g_0(6) -> 2 , g_0(8) -> 2 , g_1(3) -> 11 , g_1(5) -> 11 , g_1(6) -> 11 , g_1(8) -> 11 , mark_0(3) -> 3 , mark_0(5) -> 3 , mark_0(6) -> 3 , mark_0(8) -> 3 , mark_1(10) -> 1 , mark_1(10) -> 14 , mark_2(16) -> 15 , h_0(3) -> 4 , h_0(5) -> 4 , h_0(6) -> 4 , h_0(8) -> 4 , h_1(3) -> 12 , h_1(5) -> 12 , h_1(6) -> 12 , h_1(8) -> 12 , c_0() -> 5 , c_1() -> 13 , d_0() -> 6 , d_1() -> 10 , d_2() -> 16 , d_3() -> 18 , proper_0(3) -> 7 , proper_0(5) -> 7 , proper_0(6) -> 7 , proper_0(8) -> 7 , proper_1(3) -> 14 , proper_1(5) -> 14 , proper_1(6) -> 14 , proper_1(8) -> 14 , proper_2(10) -> 15 , proper_3(16) -> 17 , ok_0(3) -> 8 , ok_0(5) -> 8 , ok_0(6) -> 8 , ok_0(8) -> 8 , ok_1(10) -> 7 , ok_1(10) -> 14 , ok_1(11) -> 2 , ok_1(11) -> 11 , ok_1(12) -> 4 , ok_1(12) -> 12 , ok_1(13) -> 7 , ok_1(13) -> 14 , ok_2(16) -> 15 , ok_3(18) -> 17 , top_0(3) -> 9 , top_0(5) -> 9 , top_0(6) -> 9 , top_0(8) -> 9 , top_1(14) -> 9 , top_2(15) -> 9 , top_3(17) -> 9 , top_4(19) -> 9 } Hurray, we answered YES(?,O(n^1))