(VAR x y)
(RULES
  f(x,y) -> f(g(x),g(x))
  f(g(x),x) -> f(x,g(x))
  g(x) -> h(x)
  h(g(x)) -> g(g(x))
)
(COMMENT Example 4.14 of \cite{ATU2014})
(COMMENT from the collection of \cite{ATU2014})