(VAR f n x xs )
(RULES 
        app(app(f,0),n) -> app(app(hd,app(app(map,f),app(app(cons,0),nil))),n)
        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))
        
)