Natural This kind of function signifies a partial function on naturals, exactly where the proof of even (n) may very well be observed as being a precondition. In the Cambridge English Corpus There isn't any serious difference between the usual first-order objects from the mathematical discourse - for example naturals, https://vegetarianayurvedicremedies.school.blog/2025/09/03/cureayu-vegetarian-healthcare-products-natural-safe/