YES(?,O(n^1))

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

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {3,2}
   transitions:
    b1(10) -> 11*
    b1(7) -> 8*
    b1(11) -> 12*
    c1(8) -> 9*
    a0(1) -> 2*
    c0(1) -> 1*
    b0(1) -> 3*
    1 -> 7*
    8 -> 10*
    9 -> 2*
    12 -> 2*
  problem:
   
  Qed