Inserting a different font type in the same document

Question

I am using \usepackage[urw-garamond]{mathdesign} (Garamond font) for the main font in my document, but I don't like how the produced \mathcal{L} looks like. I need that L to look like in default font. I looked here, and tried loading either pxfonts or txfonts, since that has 'normal' \mathcal{L}, but no luck :|

So is it posible to combine those two?

Since I'm writing something that contains Lie derivatives I made the following swich:

\newcommand{\Lie}{ \mathcal{L}}

so I don't have to write the mathcal part over and over. But I'd like it to look 'ordinary', not extra swirly :D

Answer 1

If you have a standard font setup and don't load many other math font packages, the simplest way is to say

\documentclass{article}
\usepackage[urw-garamond]{mathdesign}

\DeclareMathAlphabet{\xcal}{OMS}{cmsy}{m}{n}
\newcommand{\Lie}{\xcal{L}}

\begin{document}
$\Lie$
\end{document}

If you want the standard calligraphic shape for all letters in \mathcal, just change the two lines with \xcal in them into

\let\mathcal\relax % "undefine" \mathcal
\DeclareMathAlphabet{\mathcal}{OMS}{cmsy}{m}{n}
\newcommand{\Lie}{\mathcal{L}}

However, if one of the above results in a "Too many math alphabets" error, there is another, albeit less efficient, strategy:

\usepackage{amsmath}
\newcommand{\xcal}[1]{\text{\usefont{OMS}{cmsy}{m}{n}#1}}
\newcommand{\Lie}{\xcal{L}}