(VAR y x xs f) (RULES app(app(ack, 0), y) -> app(succ, y) app(app(ack, app(succ, x)), y) -> app(app(ack, x), app(succ, 0)) app(app(ack, app(succ, x)), app(succ, y)) -> app(app(ack, x), app(app(ack, app(succ, x)), y)) app(app(map,f),nil) -> nil app(app(map,f),app(app(cons,x),xs)) -> app(app(cons,app(f,x)),app(app(map,f),xs)) app(app(filter,f),nil) -> nil app(app(filter,f),app(app(cons,x),xs)) -> app(app(app(app(filter2,app(f, x)),f),x),xs) app(app(app(app(filter2,true),f),x),xs) -> app(app(cons,x),app(app(filter,f),xs)) app(app(app(app(filter2,false),f),x),xs) -> app(app(filter,f),xs) )