When I tried to use the
breqn package suggested by an answer to the question
It managed to break a whole bunch of unrelated equations (equations that did not use its functionality), including a definition for the control sequence
\mf which I had previously defined myself.
Is there a way to limit the scope of a
\usepackage declaration so that its (positive and negative) effects are limited to a particular segment of a document?
I have tried putting it inside an environment, but get the following error:
! LaTeX Error: Can be used only in preamble.