Problem:
 a(a(b(x1))) -> b(a(x1))
 b(a(a(x1))) -> a(a(a(b(x1))))
 a(c(x1)) -> c(b(x1))

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {3,2}
   transitions:
    c1(5) -> 6*
    b1(4) -> 5*
    a0(1) -> 2*
    b0(1) -> 3*
    c0(1) -> 1*
    1 -> 4*
    6 -> 2*
  problem:
   
  Qed