MAYBE
Time: 0.012

Problem:
 Equations:
  +AC(+AC(x3,x4),x5) -> +AC(x3,+AC(x4,x5))
  +AC(x3,x4) -> +AC(x4,x3)
  *AC(*AC(x3,x4),x5) -> *AC(x3,*AC(x4,x5))
  *AC(x3,x4) -> *AC(x4,x3)
  UAC(UAC(x3,x4),x5) -> UAC(x3,UAC(x4,x5))
  UAC(x3,x4) -> UAC(x4,x3)
  +AC(x3,+AC(x4,x5)) -> +AC(+AC(x3,x4),x5)
  +AC(x4,x3) -> +AC(x3,x4)
  *AC(x3,*AC(x4,x5)) -> *AC(*AC(x3,x4),x5)
  *AC(x4,x3) -> *AC(x3,x4)
  UAC(x3,UAC(x4,x5)) -> UAC(UAC(x3,x4),x5)
  UAC(x4,x3) -> UAC(x3,x4)
 TRS:
  +AC(0(),x) -> x
  +AC(s(x),s(y)) -> s(s(+AC(x,y)))
  *AC(0(),x) -> 0()
  *AC(s(x),s(y)) -> s(+AC(+AC(x,y),*AC(x,y)))
  UAC(empty(),b) -> b
  sum(empty()) -> 0()
  sum(singl(x)) -> x
  sum(UAC(x,y)) -> +AC(sum(x),sum(y))
  prod(empty()) -> s(0())
  prod(singl(x)) -> x
  prod(UAC(x,y)) -> *AC(prod(x),prod(y))

Proof:
 Open