YES(?,O(n^1)) We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { active(zeros()) -> mark(cons(0(), zeros())) , active(cons(X1, X2)) -> cons(active(X1), X2) , active(and(X1, X2)) -> and(active(X1), X2) , active(and(tt(), X)) -> mark(X) , active(length(X)) -> length(active(X)) , active(length(cons(N, L))) -> mark(s(length(L))) , active(length(nil())) -> mark(0()) , active(s(X)) -> s(active(X)) , active(take(X1, X2)) -> take(X1, active(X2)) , active(take(X1, X2)) -> take(active(X1), X2) , active(take(0(), IL)) -> mark(nil()) , active(take(s(M), cons(N, IL))) -> mark(cons(N, take(M, IL))) , cons(mark(X1), X2) -> mark(cons(X1, X2)) , cons(ok(X1), ok(X2)) -> ok(cons(X1, X2)) , and(mark(X1), X2) -> mark(and(X1, X2)) , and(ok(X1), ok(X2)) -> ok(and(X1, X2)) , length(mark(X)) -> mark(length(X)) , length(ok(X)) -> ok(length(X)) , s(mark(X)) -> mark(s(X)) , s(ok(X)) -> ok(s(X)) , take(X1, mark(X2)) -> mark(take(X1, X2)) , take(mark(X1), X2) -> mark(take(X1, X2)) , take(ok(X1), ok(X2)) -> ok(take(X1, X2)) , proper(zeros()) -> ok(zeros()) , proper(cons(X1, X2)) -> cons(proper(X1), proper(X2)) , proper(0()) -> ok(0()) , proper(and(X1, X2)) -> and(proper(X1), proper(X2)) , proper(tt()) -> ok(tt()) , proper(length(X)) -> length(proper(X)) , proper(nil()) -> ok(nil()) , proper(s(X)) -> s(proper(X)) , proper(take(X1, X2)) -> take(proper(X1), proper(X2)) , 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 5. The enriched problem is compatible with the following automaton. { active_0(2) -> 1 , active_0(3) -> 1 , active_0(5) -> 1 , active_0(7) -> 1 , active_0(9) -> 1 , active_0(13) -> 1 , active_1(2) -> 23 , active_1(3) -> 23 , active_1(5) -> 23 , active_1(7) -> 23 , active_1(9) -> 23 , active_1(13) -> 23 , active_2(16) -> 24 , active_2(17) -> 24 , active_3(34) -> 30 , active_4(26) -> 36 , active_4(37) -> 38 , active_5(33) -> 39 , zeros_0() -> 2 , zeros_1() -> 17 , zeros_2() -> 27 , zeros_3() -> 35 , mark_0(2) -> 3 , mark_0(3) -> 3 , mark_0(5) -> 3 , mark_0(7) -> 3 , mark_0(9) -> 3 , mark_0(13) -> 3 , mark_1(15) -> 1 , mark_1(15) -> 23 , mark_1(18) -> 4 , mark_1(18) -> 18 , mark_1(19) -> 6 , mark_1(19) -> 19 , mark_1(20) -> 8 , mark_1(20) -> 20 , mark_1(21) -> 10 , mark_1(21) -> 21 , mark_1(22) -> 11 , mark_1(22) -> 22 , mark_2(25) -> 24 , cons_0(2, 2) -> 4 , cons_0(2, 3) -> 4 , cons_0(2, 5) -> 4 , cons_0(2, 7) -> 4 , cons_0(2, 9) -> 4 , cons_0(2, 13) -> 4 , cons_0(3, 2) -> 4 , cons_0(3, 3) -> 4 , cons_0(3, 5) -> 4 , cons_0(3, 7) -> 4 , cons_0(3, 9) -> 4 , cons_0(3, 13) -> 4 , cons_0(5, 2) -> 4 , cons_0(5, 3) -> 4 , cons_0(5, 5) -> 4 , cons_0(5, 7) -> 4 , cons_0(5, 9) -> 4 , cons_0(5, 13) -> 4 , cons_0(7, 2) -> 4 , cons_0(7, 3) -> 4 , cons_0(7, 5) -> 4 , cons_0(7, 7) -> 4 , cons_0(7, 9) -> 4 , cons_0(7, 13) -> 4 , cons_0(9, 2) -> 4 , cons_0(9, 3) -> 4 , cons_0(9, 5) -> 4 , cons_0(9, 7) -> 4 , cons_0(9, 9) -> 4 , cons_0(9, 13) -> 4 , cons_0(13, 2) -> 4 , cons_0(13, 3) -> 4 , cons_0(13, 5) -> 4 , cons_0(13, 7) -> 4 , cons_0(13, 9) -> 4 , cons_0(13, 13) -> 4 , cons_1(2, 2) -> 18 , cons_1(2, 3) -> 18 , cons_1(2, 5) -> 18 , cons_1(2, 7) -> 18 , cons_1(2, 9) -> 18 , cons_1(2, 13) -> 18 , cons_1(3, 2) -> 18 , cons_1(3, 3) -> 18 , cons_1(3, 5) -> 18 , cons_1(3, 7) -> 18 , cons_1(3, 9) -> 18 , cons_1(3, 13) -> 18 , cons_1(5, 2) -> 18 , cons_1(5, 3) -> 18 , cons_1(5, 5) -> 18 , cons_1(5, 7) -> 18 , cons_1(5, 9) -> 18 , cons_1(5, 13) -> 18 , cons_1(7, 2) -> 18 , cons_1(7, 3) -> 18 , cons_1(7, 5) -> 18 , cons_1(7, 7) -> 18 , cons_1(7, 9) -> 18 , cons_1(7, 13) -> 18 , cons_1(9, 2) -> 18 , cons_1(9, 3) -> 18 , cons_1(9, 5) -> 18 , cons_1(9, 7) -> 18 , cons_1(9, 9) -> 18 , cons_1(9, 13) -> 18 , cons_1(13, 2) -> 18 , cons_1(13, 3) -> 18 , cons_1(13, 5) -> 18 , cons_1(13, 7) -> 18 , cons_1(13, 9) -> 18 , cons_1(13, 13) -> 18 , cons_1(16, 17) -> 15 , cons_2(26, 27) -> 25 , cons_2(28, 29) -> 24 , cons_3(26, 27) -> 34 , cons_3(31, 32) -> 30 , cons_4(33, 35) -> 37 , cons_4(36, 27) -> 30 , cons_5(39, 35) -> 38 , 0_0() -> 5 , 0_1() -> 16 , 0_2() -> 26 , 0_3() -> 33 , and_0(2, 2) -> 6 , and_0(2, 3) -> 6 , and_0(2, 5) -> 6 , and_0(2, 7) -> 6 , and_0(2, 9) -> 6 , and_0(2, 13) -> 6 , and_0(3, 2) -> 6 , and_0(3, 3) -> 6 , and_0(3, 5) -> 6 , and_0(3, 7) -> 6 , and_0(3, 9) -> 6 , and_0(3, 13) -> 6 , and_0(5, 2) -> 6 , and_0(5, 3) -> 6 , and_0(5, 5) -> 6 , and_0(5, 7) -> 6 , and_0(5, 9) -> 6 , and_0(5, 13) -> 6 , and_0(7, 2) -> 6 , and_0(7, 3) -> 6 , and_0(7, 5) -> 6 , and_0(7, 7) -> 6 , and_0(7, 9) -> 6 , and_0(7, 13) -> 6 , and_0(9, 2) -> 6 , and_0(9, 3) -> 6 , and_0(9, 5) -> 6 , and_0(9, 7) -> 6 , and_0(9, 9) -> 6 , and_0(9, 13) -> 6 , and_0(13, 2) -> 6 , and_0(13, 3) -> 6 , and_0(13, 5) -> 6 , and_0(13, 7) -> 6 , and_0(13, 9) -> 6 , and_0(13, 13) -> 6 , and_1(2, 2) -> 19 , and_1(2, 3) -> 19 , and_1(2, 5) -> 19 , and_1(2, 7) -> 19 , and_1(2, 9) -> 19 , and_1(2, 13) -> 19 , and_1(3, 2) -> 19 , and_1(3, 3) -> 19 , and_1(3, 5) -> 19 , and_1(3, 7) -> 19 , and_1(3, 9) -> 19 , and_1(3, 13) -> 19 , and_1(5, 2) -> 19 , and_1(5, 3) -> 19 , and_1(5, 5) -> 19 , and_1(5, 7) -> 19 , and_1(5, 9) -> 19 , and_1(5, 13) -> 19 , and_1(7, 2) -> 19 , and_1(7, 3) -> 19 , and_1(7, 5) -> 19 , and_1(7, 7) -> 19 , and_1(7, 9) -> 19 , and_1(7, 13) -> 19 , and_1(9, 2) -> 19 , and_1(9, 3) -> 19 , and_1(9, 5) -> 19 , and_1(9, 7) -> 19 , and_1(9, 9) -> 19 , and_1(9, 13) -> 19 , and_1(13, 2) -> 19 , and_1(13, 3) -> 19 , and_1(13, 5) -> 19 , and_1(13, 7) -> 19 , and_1(13, 9) -> 19 , and_1(13, 13) -> 19 , tt_0() -> 7 , tt_1() -> 16 , tt_2() -> 26 , tt_3() -> 33 , length_0(2) -> 8 , length_0(3) -> 8 , length_0(5) -> 8 , length_0(7) -> 8 , length_0(9) -> 8 , length_0(13) -> 8 , length_1(2) -> 20 , length_1(3) -> 20 , length_1(5) -> 20 , length_1(7) -> 20 , length_1(9) -> 20 , length_1(13) -> 20 , nil_0() -> 9 , nil_1() -> 16 , nil_2() -> 26 , nil_3() -> 33 , s_0(2) -> 10 , s_0(3) -> 10 , s_0(5) -> 10 , s_0(7) -> 10 , s_0(9) -> 10 , s_0(13) -> 10 , s_1(2) -> 21 , s_1(3) -> 21 , s_1(5) -> 21 , s_1(7) -> 21 , s_1(9) -> 21 , s_1(13) -> 21 , take_0(2, 2) -> 11 , take_0(2, 3) -> 11 , take_0(2, 5) -> 11 , take_0(2, 7) -> 11 , take_0(2, 9) -> 11 , take_0(2, 13) -> 11 , take_0(3, 2) -> 11 , take_0(3, 3) -> 11 , take_0(3, 5) -> 11 , take_0(3, 7) -> 11 , take_0(3, 9) -> 11 , take_0(3, 13) -> 11 , take_0(5, 2) -> 11 , take_0(5, 3) -> 11 , take_0(5, 5) -> 11 , take_0(5, 7) -> 11 , take_0(5, 9) -> 11 , take_0(5, 13) -> 11 , take_0(7, 2) -> 11 , take_0(7, 3) -> 11 , take_0(7, 5) -> 11 , take_0(7, 7) -> 11 , take_0(7, 9) -> 11 , take_0(7, 13) -> 11 , take_0(9, 2) -> 11 , take_0(9, 3) -> 11 , take_0(9, 5) -> 11 , take_0(9, 7) -> 11 , take_0(9, 9) -> 11 , take_0(9, 13) -> 11 , take_0(13, 2) -> 11 , take_0(13, 3) -> 11 , take_0(13, 5) -> 11 , take_0(13, 7) -> 11 , take_0(13, 9) -> 11 , take_0(13, 13) -> 11 , take_1(2, 2) -> 22 , take_1(2, 3) -> 22 , take_1(2, 5) -> 22 , take_1(2, 7) -> 22 , take_1(2, 9) -> 22 , take_1(2, 13) -> 22 , take_1(3, 2) -> 22 , take_1(3, 3) -> 22 , take_1(3, 5) -> 22 , take_1(3, 7) -> 22 , take_1(3, 9) -> 22 , take_1(3, 13) -> 22 , take_1(5, 2) -> 22 , take_1(5, 3) -> 22 , take_1(5, 5) -> 22 , take_1(5, 7) -> 22 , take_1(5, 9) -> 22 , take_1(5, 13) -> 22 , take_1(7, 2) -> 22 , take_1(7, 3) -> 22 , take_1(7, 5) -> 22 , take_1(7, 7) -> 22 , take_1(7, 9) -> 22 , take_1(7, 13) -> 22 , take_1(9, 2) -> 22 , take_1(9, 3) -> 22 , take_1(9, 5) -> 22 , take_1(9, 7) -> 22 , take_1(9, 9) -> 22 , take_1(9, 13) -> 22 , take_1(13, 2) -> 22 , take_1(13, 3) -> 22 , take_1(13, 5) -> 22 , take_1(13, 7) -> 22 , take_1(13, 9) -> 22 , take_1(13, 13) -> 22 , proper_0(2) -> 12 , proper_0(3) -> 12 , proper_0(5) -> 12 , proper_0(7) -> 12 , proper_0(9) -> 12 , proper_0(13) -> 12 , proper_1(2) -> 23 , proper_1(3) -> 23 , proper_1(5) -> 23 , proper_1(7) -> 23 , proper_1(9) -> 23 , proper_1(13) -> 23 , proper_2(15) -> 24 , proper_2(16) -> 28 , proper_2(17) -> 29 , proper_3(25) -> 30 , proper_3(26) -> 31 , proper_3(27) -> 32 , ok_0(2) -> 13 , ok_0(3) -> 13 , ok_0(5) -> 13 , ok_0(7) -> 13 , ok_0(9) -> 13 , ok_0(13) -> 13 , ok_1(16) -> 12 , ok_1(16) -> 23 , ok_1(17) -> 12 , ok_1(17) -> 23 , ok_1(18) -> 4 , ok_1(18) -> 18 , ok_1(19) -> 6 , ok_1(19) -> 19 , ok_1(20) -> 8 , ok_1(20) -> 20 , ok_1(21) -> 10 , ok_1(21) -> 21 , ok_1(22) -> 11 , ok_1(22) -> 22 , ok_2(26) -> 28 , ok_2(27) -> 29 , ok_3(33) -> 31 , ok_3(34) -> 24 , ok_3(35) -> 32 , ok_4(37) -> 30 , top_0(2) -> 14 , top_0(3) -> 14 , top_0(5) -> 14 , top_0(7) -> 14 , top_0(9) -> 14 , top_0(13) -> 14 , top_1(23) -> 14 , top_2(24) -> 14 , top_3(30) -> 14 , top_4(38) -> 14 } Hurray, we answered YES(?,O(n^1))