NO Problem: a(x1) -> x1 a(b(x1)) -> b(b(c(a(x1)))) b(x1) -> x1 b(c(c(x1))) -> a(x1) Proof: Unfolding Processor: loop length: 10 terms: a(b(b(b(c(b(b(x70479))))))) b(b(c(a(b(b(c(b(b(x70479))))))))) b(b(c(b(b(c(a(b(c(b(b(x70479))))))))))) b(b(c(b(c(a(b(c(b(b(x70479)))))))))) b(b(c(c(a(b(c(b(b(x70479))))))))) b(a(a(b(c(b(b(x70479))))))) b(a(b(b(c(a(c(b(b(x70479))))))))) b(a(b(b(c(c(b(b(x70479)))))))) b(a(b(a(b(b(x70479)))))) b(a(b(b(b(c(a(b(x70479)))))))) context: b([]) substitution: x70479 -> c(a(x70479)) Qed