Natural Such a function represents a partial functionality on naturals, in which the proof of even (n) may be witnessed as being a precondition. From your Cambridge English Corpus There's no actual distinction between the usual first-order objects of the mathematical discourse - like naturals, sets and so on - https://buyyuvacenbotoxdaycream.blogspot.com/2025/09/ayurvedic-natural-remedies-for-energy.html