4

How can I make this function in LaTeX:

enter image description here

I tried with \Vmatrix as:

$\begin{Vmatrix} \bullet \end{Vmatrix}^{\mathscr{M}_i,g}$

but its not the same. If you can help me, I'd appreciate it.

Ethan Bolker
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Julián Sanabria
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2 Answers2

6

The stmaryrd package has these symbols ready to go.

If one also needs the double brace, which is not in the stmaryrd package, an alternate solution is offered at Defining scalable "white curly brackets" {| and |} (⦃ and ⦄)

Here is the MWE for the double brackets and parens.

\documentclass{article}
\usepackage{stmaryrd}
\usepackage{amssymb}
\begin{document}
\[
  \llbracket\cdot\rrbracket^{\mathcal{M}_i,g}\quad
  \left\llbracket\strut\cdot\right\rrbracket^{\mathcal{M}_i,g}
\]
\[
  \llparenthesis\cdot\rrparenthesis^{\mathcal{M}_i,g}
\]
\end{document}

enter image description here

By the way, the one should note that the double-bracket is scalable using \left\llbracket...\right\rrbracket syntax. On the other hand, the double-parens are not scalable with that syntax. However, the \stretchleftright{}{}{} syntax of the scalerel package can emulate the behavior somewhat.

\documentclass{article}
\usepackage{stmaryrd}
\usepackage{amssymb,scalerel}
\begin{document}
\[
  \left\llbracket\frac{x}{y}\right\rrbracket^{\mathcal{M}_i,g}
\]
\[
  {\stretchleftright{\llparenthesis}{\frac{x\strut}{y\strut}}{\rrparenthesis}}^{\mathcal{M}_i,g}
\]
\end{document}

enter image description here

Community
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Steven B. Segletes
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  • I don't see why using the only option; it was useful several years ago, when memory was scarce. – egreg May 11 '16 at 06:19
  • @egreg I didn't know whether stmaryrd was anything like MnSymbol, taking over the whole symbol set or not. So, since I knew this option to be available, I thought it safer. – Steven B. Segletes May 11 '16 at 10:48
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    No, stmaryrd provides a set of new symbols and redefines nothing. I seem to remember that a package loads stmaryrd with the only option, making it very difficult to use other symbols from the package. Since memory is not a problem any longer, just load the full set. – egreg May 11 '16 at 10:59
4

You can "concatenate" two square brackets using a negative \mkern:

enter image description here

\documentclass{article}

\usepackage{mathpazo}

\begin{document}

\[
  [\mkern-3.5mu[
  \cdot
  ]\mkern-3.5mu]
  ^
  {\mathcal{M}_i,g}
\]

\end{document}
Werner
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