(VAR x y z)
(RULES
*(one, x) -> x
*(i(x), x) -> one
*(*(x, y), z) -> *(x, *(y, z))
f(*(x, y)) -> *(f(x), f(y))
g(*(x, y)) -> *(g(x), g(y))
*(f(x), g(y)) -> *(g(y), f(x))
)
(COMMENT Example CGE2 in \cite{WSW07})