Half-Open Interval Brackets in LaTeX (\left[ x \right))

Where it is used

Pairs a left square bracket with a right parenthesis, the notation for a half-open interval.

\left and \right do not have to match in shape, so \left[ ... \right) writes the half-open interval [a, b), closed at a and open at b, common in probability (cumulative distribution functions are right-continuous on [x, \infty)) and in measure theory. Mismatched pairs also handle (a, b], written \left( ... \right]. For simple intervals plain [0, 1) without \left/\right is sufficient and cleaner. Some European texts use reversed brackets instead, as in [a, b[, which you can type directly.

Minimal compilable example

Paste this into an empty .tex file and compile it with pdfLaTeX, XeLaTeX or LuaLaTeX.

\documentclass{article}
\begin{document}
Half-Open Interval Brackets: $\left[ x \right)$

\[ x \in \left[ 0, \frac{\pi}{2} \right) \]
\end{document}

Related symbols

• Right Delimiter with Invisible Left\left. x \right)
• Left Delimiter with Invisible Right\left( x \right.
• Bigg Parentheses\Bigg( x \Bigg)
• Big Parentheses\Big( x \Big)
• Vertical Bar\left| x \right|
• Curly Braces\left\{ x \right\}

Frequently asked questions

How do I write Half-Open Interval Brackets in LaTeX?

Type \left[ x \right) in math mode, for example $x \in \left[ 0, \frac{\pi}{2} \right)$. It works in plain LaTeX without loading any package.

Which package do I need for \left[ x \right)?

None. \left[ x \right) is part of standard LaTeX, so it compiles with nothing in the preamble but the document class.

Can I use \left[ x \right) in text mode, or only in math mode?

Only in math mode. Outside $...$ LaTeX stops with "Missing $ inserted", so write $\left[ x \right)$ in running text.