In mathematics, the capital symbol z is used to represent the set of all integers, including positive integers, 0 and negative integers. All integers form an integer set, which is a number ring. In the integer system, zero and positive integers are collectively called natural numbers.
-1, -2, -3, …, -n, …(n is a non-zero natural number) are negative integers. Positive integers, zero integers and negative integers form an integer system. Integers exclude decimals and fractions.
Even if there is an integer of 0, it is not allowed:
About 1500 years ago, European mathematicians did not know how to use the number "0". At this time, a scholar in Rome found the symbol "0" from the counting method in India. He found it very convenient to use "0" for mathematical operation, so he introduced the method of using "0" by Indians. It was soon known to the Pope.
The Pope was very angry. He believes that the sacred number was created by God, and there is no "0" monster in the number created by God in Rome. The scholar was arrested and tortured for blasphemy. In this way, the integer "0" is not listed in Europe, which is largely one of the reasons why Arabic numerals are most commonly used in the world instead of Roman numerals.