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