I'm trying to create a command to save me some heartache when writing the rest of this document. What I'm attempting to do is to create a command like \double{-}, which when used will produce:

\llbracket - \rrbracket.

2 Answers 2


The other solution is good, and is in general the way that you'd define a command. Just to add on a little bit of handy info -- The mathtools package provides \DeclarePairedDelimiter, which is super useful for exactly this sort of thing. For example,


defines a command that simply surrounds an argument in double braces like the other answer:


or scale itself with a size parameter like \big:


or even automatically scale itself to fit whatever's inside:

\double*{\frac{\sum i}{\prod j}}

Chances are this is overkill for whatever you're doing, but it's always nice to know what's available to you, eh?


Surprisingly easy to do, simply do:

\newcommand{\double}[1]{\llbracket #1 \rrbracket}

Based on: latex newcommand guide

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