Document Classes ⇒ How to un-define a command or environment

[kaiserkarl13]

I am using a document class (in this case, the "iopart" class, intended for articles submitted to Institute of Physics journals) that contains the following commands:

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\@namedef{equation*}{\[}
\@namedef{endequation*}{\]}

These lines (which I'm certain are the result of someone attempting to be overly helpful) obviously break the amsmath package.

Is there a way to undefine an environment or command in LaTeX? I've tried something like

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\let\equation*\@undefined

or

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\let\equation*\undefined

but that still gives me errors. What I want to do is edit the class file and remove those two lines, but that isn't an option; the journal will preserve the original file when I submit the article, and I have no way to insist that they use the doctored file.

[localghost]

It seems to work if you load the package right before the document class.

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\RequirePackage{amsmath}

Side effects cannot be ruled out.


Thorsten

[cgnieder]

This is funny -- amsmath essentially does the opposite:

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\DeclareRobustCommand{\[}{\begin{equation*}}
\DeclareRobustCommand{\]}{\end{equation*}}

You can use etoolbox for undefining commands. It provides the command \csundef{<csname>}:

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\documentclass{iopart}
\usepackage{etoolbox}
\csundef{equation*}
\csundef{endequation*}

\usepackage{amsmath}
\begin{document}

\begin{equation*}
 x + y = z
\end{equation*}

\end{document}

Regards

[kaiserkarl13]

Great idea putting \RequirePackage{amsmath} before the document class. I don't actually use the equation* environment anywhere, so any side effects should be minimal. The etoolbox package is a good suggestion as well (though in this case I'm less comfortable with it, since the journal will probably not use eTex to process my files).

Thanks much!

[cgnieder]

Without etex you could do sth like this:

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\documentclass{iopart}
\expandafter\let\csname equation*\endcsname\relax
\expandafter\let\csname endequation*\endcsname\relax
\usepackage{amsmath}
...

Regards