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

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {3,2}
   transitions:
    a1(5) -> 6*
    a1(4) -> 5*
    c1(7) -> 8*
    c1(6) -> 7*
    a0(1) -> 2*
    b0(1) -> 3*
    c0(1) -> 1*
    1 -> 6,4
    5 -> 3*
    8 -> 3*
  problem:
   
  Qed