NO Problem: b(c(x1)) -> a(b(b(x1))) b(a(x1)) -> a(c(b(x1))) Proof: String Reversal Processor: c(b(x1)) -> b(b(a(x1))) a(b(x1)) -> b(c(a(x1))) Unfolding Processor: loop length: 10 terms: c(b(b(b(b(b(x6553)))))) b(b(a(b(b(b(b(x6553))))))) b(b(b(c(a(b(b(b(x6553)))))))) b(b(b(c(b(c(a(b(b(x6553))))))))) b(b(b(c(b(c(b(c(a(b(x6553)))))))))) b(b(b(c(b(b(b(a(c(a(b(x6553))))))))))) b(b(b(c(b(b(b(a(c(b(c(a(x6553)))))))))))) b(b(b(c(b(b(b(a(b(b(a(c(a(x6553))))))))))))) b(b(b(c(b(b(b(b(c(a(b(a(c(a(x6553)))))))))))))) b(b(b(c(b(b(b(b(c(b(c(a(a(c(a(x6553))))))))))))))) context: b(b(b([]))) substitution: x6553 -> b(a(c(a(a(c(a(x6553))))))) Qed