Integers
From specialfunctionswiki
The integers $\mathbb{Z}$ is the set $$\mathbb{Z}=\{\ldots,-2,-1,0,1,2,\ldots\}.$$ The positive integers $\mathbb{Z}^+$ is the set $$\mathbb{Z}^+=\{1,2,3,\ldots\}$$ and the negative integers $\mathbb{Z}^-$ is the set $$\mathbb{Z}^-=\{-1,-2,-3,\ldots\}.$$
