# 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 ]]?

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Did you mean the double brackets like in the picture in this question? tex.stackexchange.com/questions/48310/… – kahen Apr 6 '13 at 17:36
To the best of my knowledge, there isn't a multiset parenthesis pair in any of the standard fonts. See this question: tex.stackexchange.com/questions/5816/multiset-notation-in-latex – kahen Apr 6 '13 at 17:38
yes that double brackets. but also for ((A,B))! – user28592 Apr 6 '13 at 17:40
For double parentheses see this question: A symbol for the field of formal Laurent series. – Hendrik Vogt Apr 6 '13 at 18:34
@SeanAllred Your comment seems to be an answer – egreg Apr 7 '13 at 22:43

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 $(\!( a^2 )\!)$.


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.

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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