MAYBE
Time: 0.012

Problem:
 Equations:
  fAC(fAC(x3,x4),x5) -> fAC(x3,fAC(x4,x5))
  fAC(x3,x4) -> fAC(x4,x3)
  fAC(x3,fAC(x4,x5)) -> fAC(fAC(x3,x4),x5)
  fAC(x4,x3) -> fAC(x3,x4)
 TRS:
  g(fAC(x,y)) -> fAC(g(x),g(y))
  fAC(g(a()),g(a())) -> fAC(a(),g(g(a())))

Proof:
 Open