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