# Vertical bar

A vertical bar is the glyph "|". It has several other names besides vertical bar, such as "pipe", "vertical slash", and "bar". In mathematics, it may be put on both sides of a real or complex number to mean its absolute value. When applied on both sides of a matrix, it means its determinant. When placed in between two numbers, it means the divisibility relation (for example. $a\mid b$ means "a divides b").
In mathematics, double vertical bars are also used to refer to various mathematical concepts. These include the parallel relation (as in $\ell _{1}\parallel \ell _{2}$ ) and the norm of a vector (as in $\|\mathbf {v} \|$ ).<iframe width="200" height="166" src="https://www.youtube.com/embed/VZkp_YTZU8E" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe><script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script> <script>
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