The Extended Real Numbers#
Definition: The Extended Real Numbers
The extended real numbers are the union of the real numbers with the set containing the symbols \(-\infty\) and \(+\infty\):
\[ \mathbb{R} \cup \{-\infty, +\infty\} \]
Notation
\[ \overline{\mathbb{R}} \qquad [-\infty;+\infty] \qquad \mathbb{R} \cup \{-\infty, +\infty\} \]