(VAR x y)
(THEORY (AC plus times))
(RULES
  plus(x, 0) -> x
  plus(x, s(y)) -> s(plus(x, y))
  times(x, 0) -> 0
  times(x, s(y)) -> plus(x, times(x, y))
  power(x, 0) -> s(0)
  power(x, s(y)) -> times(x, power(x, y))
)