NO Problem: b(a(a(x1))) -> a(x1) a(a(a(x1))) -> b(b(b(x1))) b(b(x1)) -> a(b(a(x1))) Proof: Unfolding Processor: loop length: 6 terms: a(a(a(b(a(a(x2855)))))) b(b(b(b(a(a(x2855)))))) a(b(a(b(b(a(a(x2855))))))) a(b(a(a(b(a(a(a(x2855)))))))) a(b(a(a(b(b(b(b(x2855)))))))) a(b(a(a(a(b(a(b(b(x2855))))))))) context: a(b([])) substitution: x2855 -> b(a(x2855)) Qed