(CONDITIONTYPE ORIENTED) (VAR x y) (RULES a -> c a -> d b -> c b -> d s(k) -> t(a) s(l) -> t(a) g(x, x) -> h(x, x) f(x, y) -> y | s(x) == t(y) ) (COMMENT \cite{G14}, example 28 PhD Thesis, not yet published )