Barbara, > here's what it says in the file technote.tex that's distributed with the > ams-latex collection. > ... > Users have proposed two workarounds (September 1996): > .... Both of those workarounds always looked odd to me, as as far as I can see the code goes to some lengths to make the following construction work, but then doesn't tell anyone about it. The same thing works for essentially the same reasons in the verbatim and tabularx package environments, those package document this though. David \documentclass[]{article} \usepackage[]{amsmath} \newenvironment{fancyequation} {\hrule \equation} {\endequation\hrule} \begin{document} \begin{fancyequation} a = b \end{fancyequation} \end{document}