NO Problem: f(b()) -> b() b() -> h(h(c(),f(b())),a()) Proof: Nonconfluence Processor: terms: f(h(h(c(),f(h(h(c(),f(h(h(c(),f(b())),a()))),a()))),a())) *<- f(b()) ->* h(h(c(),f(h(h(c(),f(b())),a()))),a()) Qed