MAYBE
Time: 0.010

Problem:
 Equations:
  joinAC(joinAC(x3,x4),x5) -> joinAC(x3,joinAC(x4,x5))
  joinAC(x3,x4) -> joinAC(x4,x3)
  meetAC(meetAC(x3,x4),x5) -> meetAC(x3,meetAC(x4,x5))
  meetAC(x3,x4) -> meetAC(x4,x3)
  joinAC(x3,joinAC(x4,x5)) -> joinAC(joinAC(x3,x4),x5)
  joinAC(x4,x3) -> joinAC(x3,x4)
  meetAC(x3,meetAC(x4,x5)) -> meetAC(meetAC(x3,x4),x5)
  meetAC(x4,x3) -> meetAC(x3,x4)
 TRS:
  joinAC(x,meetAC(x,y)) -> x
  meetAC(x,joinAC(x,y)) -> x
  joinAC(x,meetAC(y,z)) -> meetAC(joinAC(x,y),joinAC(x,z))

Proof:
 Open