A function or operation that satisfies the linear property, that is, it satisfies the conditions that addition is interchangeable, addition can be combined, addition has a unit element, and number multiplication satisfies the law of association and distribution. Overlimit number is a number larger than real number, which can be used to solve some problems in infinite axiom set theory. The concept of remainder was first put forward by German mathematician Cantor at the end of 19, and it has been widely used in the fields of set theory and logic.