MAYBE We are left with following problem, upon which TcT provides the certificate MAYBE. Strict Trs: { f(x, a(b(y))) -> f(c(d(x)), y) , f(c(x), y) -> f(x, a(y)) , f(d(x), y) -> f(x, b(y)) } Obligation: innermost runtime complexity Answer: MAYBE The input cannot be shown compatible Arrrr..