Symbols:Arithmetic and Algebra/Absolute Value

Absolute Value

 * $\size x$

The absolute value of the variable $x$, when $x \in \R$.

$\size x = \begin {cases} x & : x > 0 \\ 0 & : x = 0 \\ -x & : x < 0 \end {cases}$

Also see
See Set Theory, Complex Analysis and Abstract Algebra for alternative definitions of this symbol.