YES(?,O(n^1))

Problem:
 g(a()) -> g(b())
 b() -> f(a(),a())
 f(a(),a()) -> g(d())

Proof:
 Bounds Processor:
  bound: 3
  enrichment: match
  automaton:
   final states: {6}
   transitions:
    d3() -> 16*
    g1(8) -> 6*
    d1() -> 8*
    f1(9,9) -> 6*
    a1() -> 9*
    b1() -> 8*
    g2(15) -> 6*
    g0(6) -> 6*
    d2() -> 15*
    a0() -> 6*
    f2(12,12) -> 8*
    b0() -> 6*
    a2() -> 12*
    f0(6,6) -> 6*
    g3(16) -> 8*
    d0() -> 6*
  problem:
   
  Qed