(VAR x y z)
(THEORY (AC f h))
(RULES
f(h(g(g(x)),x), g(f(x,y))) -> f(h(g(x),g(x)), f(g(x),y))
h(f(x,y),x) -> f(h(x,y),x)
f(g(x),y) -> g(f(x,y))
)