Problem: f(g(x),s(0()),y) -> f(y,y,g(x)) g(s(x)) -> s(g(x)) g(0()) -> 0() Proof: Unfolding Processor: loop length: 3 terms: f(g(s(0())),g(s(0())),g(s(0()))) f(g(s(0())),s(g(0())),g(s(0()))) f(g(s(0())),s(0()),g(s(0()))) context: [] substitution: Qed