Definition:Positive/Real Number

Definition
The positive real numbers are the set:
 * $\R_{\ge 0} = \left\{{x \in \R: x \ge 0}\right\}$

That is, all the real numbers that are greater than or equal to zero.

Also known as
In order to remove all confusion as to whether positive real number is intended to mean strictly positive real number, the use of the term non-negative real number is often recommended instead.

The -specific notation $\R_{\ge 0}$ is actually non-standard. The conventional symbols to denote this concept are $\R_+$ and $\R^+$, but these can be confused with the set $\left\{{x \in \R: x > 0}\right\}$.