YES(?,O(n^1)) We are left with following problem, upon which TcT provides the certificate YES(?,O(n^1)). Strict Trs: { a__g(X) -> a__h(X) , a__g(X) -> g(X) , a__h(X) -> h(X) , a__h(d()) -> a__g(c()) , a__c() -> d() , a__c() -> c() , mark(d()) -> d() , mark(c()) -> a__c() , mark(g(X)) -> a__g(X) , mark(h(X)) -> a__h(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__g_0(2) -> 1 , a__g_1(2) -> 1 , a__g_1(3) -> 1 , a__h_0(2) -> 1 , a__h_1(2) -> 1 , a__h_2(2) -> 1 , a__h_2(3) -> 1 , a__c_0() -> 1 , a__c_1() -> 1 , d_0() -> 2 , d_1() -> 1 , d_2() -> 1 , c_0() -> 2 , c_1() -> 1 , c_1() -> 3 , c_2() -> 1 , mark_0(2) -> 1 , g_0(2) -> 2 , g_1(2) -> 1 , g_2(2) -> 1 , g_2(3) -> 1 , h_0(2) -> 2 , h_1(2) -> 1 , h_2(2) -> 1 , h_3(2) -> 1 , h_3(3) -> 1 } Hurray, we answered YES(?,O(n^1))