MAYBE
Time: 0.074

Problem:
 Equations:
  plusAC(plusAC(x2,x3),x4) -> plusAC(x2,plusAC(x3,x4))
  plusAC(x2,x3) -> plusAC(x3,x2)
  plusAC(x2,plusAC(x3,x4)) -> plusAC(plusAC(x2,x3),x4)
  plusAC(x3,x2) -> plusAC(x2,x3)
 TRS:
  plusAC(x,0()) -> x
  plusAC(x,s(y)) -> s(plusAC(x,y))

Proof:
 DP Processor:
  Equations#:
   plus{AC,#}(plusAC(x2,x3),x4) -> plus{AC,#}(x2,plusAC(x3,x4))
   plus{AC,#}(x2,x3) -> plus{AC,#}(x3,x2)
   plus{AC,#}(x2,plusAC(x3,x4)) -> plus{AC,#}(plusAC(x2,x3),x4)
   plus{AC,#}(x3,x2) -> plus{AC,#}(x2,x3)
  DPs:
   plus{AC,#}(x,s(y)) -> plus{AC,#}(x,y)
   plus{AC,#}(x5,plusAC(x,0())) -> plus{AC,#}(x5,x)
   plus{AC,#}(x6,plusAC(x,s(y))) -> plus{AC,#}(x,y)
   plus{AC,#}(x6,plusAC(x,s(y))) -> plus{AC,#}(x6,s(plusAC(x,y)))
  Equations:
   plusAC(plusAC(x2,x3),x4) -> plusAC(x2,plusAC(x3,x4))
   plusAC(x2,x3) -> plusAC(x3,x2)
   plusAC(x2,plusAC(x3,x4)) -> plusAC(plusAC(x2,x3),x4)
   plusAC(x3,x2) -> plusAC(x2,x3)
  TRS:
   plusAC(x,0()) -> x
   plusAC(x,s(y)) -> s(plusAC(x,y))
  S:
   plus{AC,#}(plusAC(x7,x8),x9) -> plus{AC,#}(x7,x8)
   plus{AC,#}(x7,plusAC(x8,x9)) -> plus{AC,#}(x8,x9)
  Open