# Extend double vertical bar

I'm trying to write an expression in math mode similar to this formula:

My LaTeX expression looks like this:

\min \| \begin{array}{c} ... \end{array} \|


but it happens that the double lines are short:

How can I extend the double vertical bar?

Use the \left ... \right construction. See page 60 and table 3.8 of the Not so short intro. to LaTeX for further details.
\documentclass{article}
$\min \left\| \begin{bmatrix} A\\ \vdots \\ C\end{bmatrix} \right\|$

• What does one do if one doesn't need the corresponding \left delimiter? LaTeX complains if it is not present. – Abhinav Feb 11 '16 at 21:12