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