# Double square brackets

In many equation editors (e.g. MS Word 2007 and Daum Equation Editor), there's a double square bracket. Is there a TeX equivalent for [[, ((, )), and ]]?

If you only want then occasionally, perhaps you can just roll-your-own by using a little bit of negative space, like this

Maths in double brackets $[\![ e=mc^2 ]\!]$ or double parentheses $(\!( a^2 )\!)$.


Note that they will not scale nicely with \left and \right because of the fixed negative space.

If you'll be using them a lot, try using a package like stmaryrd that defines commands for these symbols, as recommended in the comments.

\documentclass{article}
\usepackage{stmaryrd}

\begin{document}

$$\llbracket 1 \rrbracket \quad \llparenthesis 2 \rrparenthesis \quad \llceil 3 \rrceil \quad \llfloor 4 \rrfloor \quad$$

\end{document}


Note especially the fancier display for double parentheses.

As a side note, DetTeXify is getting better and better at recognizing these symbols, so you can check there for more package-based options.

• thanks. for double parentheses I prefer the inner line be a curve to some extent like this one i.stack.imgur.com/bVfPz.png. however \llparenthesis is good. – user28592 Apr 8 '13 at 9:51