Number sets such as natural numbers (
There are two packages which provide the same set of symbols. You can choose to load either of them:
\usepackage{amsfonts}
% or
\usepackage{amssymb}
Now, you have access to the different set symbols through this command in math mode:
$\mathbb{set}$
Examples:
\mathbb{P}
,\mathbb{W}
,\mathbb{N}
,\mathbb{Z}
,\mathbb{I}
,\mathbb{Q}
,\mathbb{R}
and\mathbb{C}
.
\mathbb{H}
,\mathbb{O}
and\mathbb{S}
Positive and non-negative real numbers,
$\mathbb{R}_{>0}$
$\mathbb{R}_{\geq 0}$