Definition:Extended Real Number
From ProofWiki
Definition
The extended real numbers is the set of real numbers together with two values, $\R \cup \left\{{+\infty, -\infty}\right\}$ where $+\infty, -\infty$ have the properties
- $\forall x \in \R, x < +\infty$
- $\forall x \in \R, x > -\infty$
This set is often denoted $\overline{\R}$.
