TIMEOUT We are left with following problem, upon which TcT provides the certificate TIMEOUT. Strict Trs: { a__from(X) -> cons(mark(X), from(s(X))) , a__from(X) -> from(X) , mark(cons(X1, X2)) -> cons(mark(X1), X2) , mark(from(X)) -> a__from(mark(X)) , mark(s(X)) -> s(mark(X)) , mark(nil()) -> nil() , mark(0()) -> 0() , mark(length(X)) -> a__length(X) , mark(length1(X)) -> a__length1(X) , a__length(X) -> length(X) , a__length(cons(X, Y)) -> s(a__length1(Y)) , a__length(nil()) -> 0() , a__length1(X) -> a__length(X) , a__length1(X) -> length1(X) } Obligation: innermost runtime complexity Answer: TIMEOUT Computation stopped due to timeout after 10.0 seconds. Arrrr..