How to use a calligraphy package only for part of the document

Question

I need to write up a calculation that requires a lowercase calligraphic b, which I got from the following package:

\usepackage[cal=dutchcal]{mathalfa}

However, now other calligraphic letters which I was using, like $\mathcal{L}$ are in the dutchcal font, which is not what I want. Is there any way to only apply the package to specific sections of the document/equations?

Answer 1

This answer describes how to load the dutchcal fonts without loading the dutchcal package which overrides the default \mathcal macro.

Then, you can save the default \mathcal macro and override it (using \let) only for the desired part of the document. Here is a working example:

\documentclass{article}

% Save the default \mathcal
\let\mathcaldefault\mathcal

% Load the dutchcal font
\DeclareMathAlphabet{\mathdutchcal}{U}{dutchcal}{m}{n}

\begin{document}

% \mathcal and \mathdutchcal should NOT appear the same
$A, \mathdutchcal{A}, \mathcal{A}$

% Override \mathcal for this part
\let\mathcal\mathdutchcal

% \mathcal and \mathdutchcal should appear the same
$A, \mathdutchcal{A}, \mathcal{A}$

% Reset \mathcal to \mathcaldefault
\let\mathcal\mathcaldefault

% \mathcal and \mathdutchcal should NOT appear the same
$A, \mathdutchcal{A}, \mathcal{A}$

\end{document}