YES(?,O(n^1))

Problem:
 p(p(b(a(x0)),x1),p(x2,x3)) -> p(p(b(x2),a(a(b(x1)))),p(x3,x0))

Proof:
 Bounds Processor:
  bound: 1
  enrichment: match
  automaton:
   final states: {4}
   transitions:
    p1(4,4) -> 11*
    p1(15,21) -> 16*
    p1(11,4) -> 11*
    p1(12,21) -> 16*
    p1(15,14) -> 16*
    p1(16,11) -> 11,4
    b1(14) -> 19*
    b1(4) -> 15,12
    b1(21) -> 19*
    b1(16) -> 15*
    b1(11) -> 12*
    a1(20) -> 21*
    a1(12) -> 13*
    a1(19) -> 20*
    a1(13) -> 14*
    p0(4,4) -> 4*
    b0(4) -> 4*
    a0(4) -> 4*
  problem:
   
  Qed