# LaTeX minimal + refcheck + equation

The following LaTeX components do not work together in combination:

• the document class minimal
• the package refcheck
• the equation environment

Though the article class seems to work OK.

Error Message
! Undefined control sequence.
\unl@bld@mark ->{\mark@size
\textup {\{\textbf {?}\}}}
l.7


The following code recreates the failure condition.

\documentclass{minimal} %%% but works fine with article class ***
\usepackage{refcheck}
\begin{document}
$$...$$
\end{document}


The following version information has been taken from the log file.

This is XeTeX, Version 3.14159265-2.6-0.99992 (TeX Live 2015/dev/Debian)
(preloaded format=xelatex 2015.12.9) 21 FEB 2016 14:26
entering extended mode
restricted \write18 enabled.
LaTeX2e <2014/05/01>
Babel <3.9l> and hyphenation patterns for 2 languages loaded.
(/usr/share/texlive/texmf-dist/tex/latex/base/minimal.cls
Document Class: minimal 2001/05/25 Standard LaTeX minimal class
LaTeX Font Info:
External font ‘cmex10’ loaded for size


Remarks: This is almost certainly a bug in the refcheck package?

It's very simple: you should never use the minimal class for typesetting, see Why should the minimal class be avoided?

The class was written just for testing the loading of packages with options and was never meant for document production.

In this case the error is due to the fact that refcheck.sty does

\let\mark@size=\footnotesize


but the minimal class doesn't define \footnotesize: it just features \normalsize.

If you do

\documentclass{minimal}
\usepackage{refcheck}

\makeatletter
\let\mark@size\normalsize
\makeatother

\begin{document}
$$...$$

\end{document}


then no error is raised.