MAYBE
Time: 0.010

Problem:
 Equations:
  pAC(pAC(x3,x4),x5) -> pAC(x3,pAC(x4,x5))
  pAC(x3,x4) -> pAC(x4,x3)
  mAC(mAC(x3,x4),x5) -> mAC(x3,mAC(x4,x5))
  mAC(x3,x4) -> mAC(x4,x3)
  pAC(x3,pAC(x4,x5)) -> pAC(pAC(x3,x4),x5)
  pAC(x4,x3) -> pAC(x3,x4)
  mAC(x3,mAC(x4,x5)) -> mAC(mAC(x3,x4),x5)
  mAC(x4,x3) -> mAC(x3,x4)
 TRS:
  pAC(x,zero()) -> x
  mAC(x,zero()) -> zero()
  pAC(s(x),y) -> s(pAC(x,y))
  mAC(s(x),y) -> pAC(mAC(x,y),y)
  mAC(x,pAC(y,z)) -> pAC(mAC(x,y),mAC(x,z))

Proof:
 Open