NO Problem: p(x) -> q(x) p(x) -> r(x) q(x) -> s(p(x)) r(x) -> s(p(x)) s(x) -> f(p(x)) Proof: Unfolding Processor: loop length: 2 terms: p(x3) q(x3) context: s([]) substitution: x3 -> x3 Qed