A real number set is a set that contains all rational numbers and irrational numbers, and is usually represented by the capital letter R.

The axiom of real number set is: Let A and B be two sets contained in R, and for any X belonging to A and Y belonging to B, there is X.

Extended data:

Common subset of r:

1、Q

The set of rational numbers, that is, the set of all rational numbers, is represented by the bold letter Q, and the set of rational numbers is a subset of the set of real numbers.

2、N+

The set of positive integers is the set of all positive integers and integers, excluding 0 from the set of natural numbers until infinity. Positive integer sets usually use symbols N+, N*, N 1, N >；; 0 means.

3、Z

A set of all integers is called an integer set. It includes all positive integers, all negative integers and zeros. In mathematics, integer sets are usually represented by z.

References:

R (Mathematical Symbol) _ Baidu Encyclopedia