NO Problem: +(0(),0()) -> 0() +(s(0()),y) -> s(+(0(),y)) +(x,s(y)) -> s(+(y,x)) s(s(x)) -> x Proof: Nonconfluence Processor: terms: +(f5(),f6()) *<- +(f5(),s(s(f6()))) ->* s(+(s(f6()),f5())) Qed first automaton: final states: {3} transitions: f6() -> 4* +(5,4) -> 3* f5() -> 5* second automaton: final states: {6} transitions: f6() -> 8* +(9,7) -> 10* s(8) -> 9* s(10) -> 6* f5() -> 7*