TIMEOUT We are left with following problem, upon which TcT provides the certificate TIMEOUT. Strict Trs: { not(tt()) -> ff() , not(ff()) -> tt() , or(tt(), x) -> tt() , or(ff(), x) -> x , eq(0(), 0()) -> tt() , eq(0(), s(y)) -> ff() , eq(s(x), 0()) -> ff() , eq(s(x), s(y)) -> eq(x, y) , main(phi) -> ver(phi, nil()) , ver(Var(x), t()) -> in(x, t()) , ver(Or(phi, psi), t()) -> or(ver(phi, t()), ver(psi, t())) , ver(Not(phi), t()) -> not(ver(phi, t())) , ver(Exists(n, phi), t()) -> or(ver(phi, cons(n, t())), ver(phi, t())) , in(x, nil()) -> ff() , in(x, cons(a, l)) -> or(eq(x, a), in(x, l)) } Obligation: innermost runtime complexity Answer: TIMEOUT Computation stopped due to timeout after 300.0 seconds. Arrrr..