After reading an article by Grätzer in the current AMS-Notices on the STIX fonts, I wanted to use one of the math symbols in the article I am currently writing.

In perfect naivety I did what was suggested: I put the line `\RequirePackage{stix}`

as the first line in the doc.

OK, you already know what happened: The article had no resemblance to its former shape anymore and had become completely unreadable.

Here my scenario: I want to use only some selected math symbols of the STIX fonts and otherwise maintain everything else as before. What it the best way to proceed?

What I want are only the delimiters `\lbrbrak`

and `\rbrbrak`

from STIX.

```
\RequirePackage{stix}
\documentclass{amsart}
%\DeclareFontEncoding{LS1}{}{}
%\DeclareFontSubstitution{LS1}{stix}{m}{n}
%\DeclareSymbolFont{largesymbols} {LS1}{stixsf}{m} {n}
%\DeclareMathDelimiter{\lbrbrak} {\mathrel}{largesymbols}{"EE}{largesymbols}{"EE}
%\DeclareMathDelimiter{\rbrbrak} {\mathrel}{largesymbols}{"EF}{largesymbols}{"EF}
\newcommand{\newbrak}[2]{\genfrac{\lbrbrak}{\rbrbrak}{0pt}{}{#1}{#2}}
\begin{document}
\begin{equation}
\newbrak{k}{m} =
(m n)! \, \frac{\Omega_{k}(z)}{\Omega_{m}(z)}
\end{equation}
\end{document}
```

This script works. The lines beginning with 'Declare…' try to mimic the answer of David below. However out-commenting the first line and un-commenting the 'Declare..' lines leads to the error 'Insufficient extension fonts.' What did I do wrong?

## Best Answer

Here's how to add the requested symbols. You don't have correctly identified the required fonts and symbols.

Look for

`\lbrbrak`

in`stix.sty`

, to findThus we need to see what font

`largesymbols`

refers to:OK, now we need

`LS2`

:Next we have to choose a different symbolic name for the math font and put the pieces together (in reverse order).