NO Problem: a() -> h(f(a()),c()) a() -> f(c()) Proof: Nonconfluence Processor: terms: f(c()) *<- a() ->* h(f(a()),c()) Qed first automaton: final states: {1} transitions: f(2) -> 1* c() -> 2* second automaton: final states: {3} transitions: h(6,4) -> 5,3 a() -> 5* f(4) -> 5* f(5) -> 6* c() -> 4*