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(g(h(f(X)))) , active(h(X)) -> h(active(X)) , f(mark(X)) -> mark(f(X)) , f(ok(X)) -> ok(f(X)) , g(ok(X)) -> ok(g(X)) , h(mark(X)) -> mark(h(X)) , h(ok(X)) -> ok(h(X)) , proper(f(X)) -> f(proper(X)) , proper(g(X)) -> g(proper(X)) , proper(h(X)) -> h(proper(X)) , 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 1. The enriched problem is compatible with the following automaton. { active_0(3) -> 1 , active_0(7) -> 1 , active_1(3) -> 12 , active_1(7) -> 12 , f_0(3) -> 2 , f_0(7) -> 2 , f_1(3) -> 9 , f_1(7) -> 9 , mark_0(3) -> 3 , mark_0(7) -> 3 , mark_1(9) -> 2 , mark_1(9) -> 9 , mark_1(11) -> 5 , mark_1(11) -> 11 , g_0(3) -> 4 , g_0(7) -> 4 , g_1(3) -> 10 , g_1(7) -> 10 , h_0(3) -> 5 , h_0(7) -> 5 , h_1(3) -> 11 , h_1(7) -> 11 , proper_0(3) -> 6 , proper_0(7) -> 6 , proper_1(3) -> 12 , proper_1(7) -> 12 , ok_0(3) -> 7 , ok_0(7) -> 7 , ok_1(9) -> 2 , ok_1(9) -> 9 , ok_1(10) -> 4 , ok_1(10) -> 10 , ok_1(11) -> 5 , ok_1(11) -> 11 , top_0(3) -> 8 , top_0(7) -> 8 , top_1(12) -> 8 } Hurray, we answered YES(?,O(n^1))