YES
Time: 0.010

Problem:
 Equations:
  fAC(fAC(x2,x3),x4) -> fAC(x2,fAC(x3,x4))
  fAC(x2,x3) -> fAC(x3,x2)
  fAC(x2,fAC(x3,x4)) -> fAC(fAC(x2,x3),x4)
  fAC(x3,x2) -> fAC(x2,x3)
 TRS:
  fAC(x,one()) -> x
  fAC(i(x),x) -> one()
  g(one()) -> one()
  g(fAC(x,y)) -> fAC(g(x),g(y))

Proof:
 AC-RPO Processor:
  precedence:
   g > fAC > one > i
  status:
   
  problem:
   Equations:
    fAC(fAC(x2,x3),x4) -> fAC(x2,fAC(x3,x4))
    fAC(x2,x3) -> fAC(x3,x2)
    fAC(x2,fAC(x3,x4)) -> fAC(fAC(x2,x3),x4)
    fAC(x3,x2) -> fAC(x2,x3)
   TRS:
    
  Qed