Problem:
 f(a(),a()) -> c()
 f(b(),x) -> f(x,x)
 f(x,b()) -> f(x,x)
 a() -> b()

Proof:
 Nonconfluence Processor:
  terms: f(b(),b()) *<- f(a(),a()) ->* c()
  Qed
  
  first automaton:
   final states: {8}
   transitions:
    b() -> 10,9
    f(10,9) -> 8*
    f(9,9) -> 8*
    f(10,10) -> 8*
  
  second automaton:
   final states: {4}
   transitions:
    c() -> 4*