# Contents

## Idea

The sign function on the real numbers

## Definition

$\array{ \mathbb{R} &\overset{sgn}{\longrightarrow}& \mathbb{R} \\ x &\mapsto& \left\{ \array{ 1 &\vert& x \gt 0 \\ 0 &\vert& x = 0 \\ -1 &\vert& x \lt 0 }\right. }$

# Related concepts

## References

See also

Created on November 20, 2017 at 10:07:22. See the history of this page for a list of all contributions to it.