Problem: a(b(a(b(x)))) -> b(a(b(a(a(b(x)))))) Proof: Unfolding Processor: loop length: 2 terms: a(b(a(b(a(b(x5)))))) b(a(b(a(a(b(a(b(x5)))))))) context: b([]) substitution: x5 -> a(a(b(x5))) Qed