(VAR x y)
(RULES
f(a) -> b
f(c) -> d
f(g(x,y)) -> g(f(x),f(y))
f(h(x,y)) -> g(h(y,f(x)),h(x,f(y)))
g(x,x) -> h(e,x)
)

(COMMENT Example 4.53 in \cite{SK90})