(VAR x y) (RULES app(app(minus, x), 0) -> x app(app(minus, app(s, x)), app(s, y)) -> app(app(minus, x), y) app(app(quot, 0), app(s, y)) -> 0 app(app(quot, app(s, x)), app(s, y)) -> app(s, app(app(quot, app(app(minus, x), y)), app(s, y))) app(log, app(s, 0)) -> 0 app(log, app(s, app(s, x))) -> app(s, app(log, app(s, app(app(quot, x), app(s, app(s, 0)))))) )