NO Problem: a(a(b(b(x)))) -> b(b(b(a(a(a(x)))))) c(x) -> c(a(x)) c(x) -> c(b(x)) Proof: Nonconfluence Processor: terms: c(a(b(f15()))) *<- c(f15()) ->* c(a(f15())) Qed first automaton: final states: {15} transitions: b(16) -> 17* b(18) -> 18* a(18) -> 18* a(17) -> 18* f15() -> 16* c(18) -> 15* second automaton: final states: {4} transitions: b(6) -> 6* a(5) -> 6* a(6) -> 6* f15() -> 5* c(6) -> 4*