## LaTeX forum ⇒ Math & Science ⇒ apparent tilde/breve bug in amsmath

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ngrube
Posts: 2
Joined: Sun Oct 02, 2011 10:30 pm

### apparent tilde/breve bug in amsmath

Hi,

I have encountered what appears to be a bug in the amsmath package related to nested tildes and/or breves. I would be grateful for suggestions on where to report this and/or on workarounds. I already sent an email to a tech support address at AMS, but I was not certain whether that was the right thing to do. This is my first attempt at reporting a bug.

An minimum working example follows. The error is that the j from the first equation is somehow remembered and shows up unexpectedly in the second and third equations. If I comment out the amsmath package, then it works correctly.

Thanks,
Nathan Grube

\documentclass[11pt]{article}\usepackage{geometry}                \geometry{letterpaper}\usepackage[]{amsmath}\begin{document} \begin{equation}\breve{\tilde{j}}\end{equation} \begin{equation}\breve{\breve{{T}} \breve{{v}}}\end{equation}\begin{equation}\tilde{{\tilde{T}} {\tilde{v}}}\end{equation} \end{document}
Last edited by Stefan Kottwitz on Sun Oct 02, 2011 11:42 pm, edited 1 time in total.

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Stefan Kottwitz
Posts: 9436
Joined: Mon Mar 10, 2008 9:44 pm
Hi Nathan,

that's interesting!

Here's a quick workaround: use

\smash{\vphantom{$\breve{}$}}

or probably better

\makeatletter\global\let\macc@nucleus\@empty\makeatother

before the next equation which showed that problem.

Stefan

ngrube
Posts: 2
Joined: Sun Oct 02, 2011 10:30 pm
Thank you, Stefan! That fixes my problem.

Stefan Kottwitz
Posts: 9436
Joined: Mon Mar 10, 2008 9:44 pm
Hi Nathan,

it seems to be a known bug in amsmath, which is on the list for the next overhaul of the package. This can be read on TeX.SX, also another fix, I posted the problem there for hopefully finding a better fix:

Why do arguments to nested \tilde or \breve commands reappear when amsmath is used?

Stefan