The mathematical symbol z represents a set of integers. A set of all integers is called an integer set. It includes all positive integers, all negative integers and zeros. In mathematics, the integer set is usually represented by Z. Why should the extended data be represented by Z?

This involves the contribution of a German female mathematician to ring theory. Her name is Nott.

In 1920, she introduced the concepts of "left module" and "right module". The ideal theory of the whole ring written in 192 1 is a milestone in the development of commutative algebra. Among them, when Nott introduced the concept of integer ring (integer set itself is also a number ring), she was German, and the integer in German was called Zahlen, so she recorded the integer ring as Z at that time, and the integer set has been represented by Z ever since.

What is a positive integer set?

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

Where n stands for natural number set, z stands for integer set,+stands for all elements in number set are positive numbers, * stands for number set excluding element 0 (for example, R* stands for number set excluding element 0 in R, that is, R*=R{0}=R-∪R+=(-∞, 0)∩(0,+).

There are positive numbers and negative numbers in mathematics, which are represented by the number axis. The starting point is zero, the arrow pointing (usually to the right) is positive, and the arrow pointing in the opposite direction (usually to the left) is negative. A set is a structure that includes several objects (it can include 0 objects, that is, an empty set).