# Delimiters \left( and \right) do not work (fourier and teubner)

Sorry i posted a totally useless long post. I reproduced now the very same issue thanx to the comments of daleif. Here it is:

MWE:

\documentclass{memoir}

\usepackage[polutonikogreek, italian,english]{babel}

\usepackage[sc]{mathpazo}
\usepackage{fourier}
\usepackage{teubner}

\begin{document}

$$\label{taus} \tau_e=\left(\frac{N_r\sigma_e}{v_{th}}\right)^{-1}$$

\end{document}

• (1) This can easily be put into a single MWE (replace \LoadClass by \documentclass (2) Unrelated, you should never use fancyhdr with memoir, the classes own pagestyle system is much much more integrated into the class. Mar 18 '20 at 21:37
• The class is loading both fourier and mathpazo this is well know to cause issues, if I remove fourier the fences work again. Just mathpazo is not enough Mar 18 '20 at 21:38
• teubner and fourier does not seem to like each other. There are many things in this template that we generally do not recommend. Mar 18 '20 at 21:43
• Thank you i was lost in finding the conflict but now you pointed out the two packages in conflict the MWE was reduced to the bone as you suggested. A sub-problem is now that the two packages behave differently if called in reversed order. Mar 18 '20 at 22:06

1. The packages teubner and fourier don't cooperate well.
2. Never load two packages that define math fonts: either mathpazo (for Palatino) or fourier (for Utopia).

Next, loading teubner after fourier seems to fix the issues, but it doesn't.

and you see that \left and \right don't do their job.

\documentclass{article}

\usepackage[polutonikogreek, italian, english]{babel}

\usepackage{teubner}
\let\teubnerbreve\breve
\let\breve\relax
\usepackage{fourier}
\let\mbreve\breve
\let\breve\teubnerbreve

\begin{document}

$$\label{taus} \tau_e=\left(\frac{N_r\sigma_e}{v_{th}}\right)^{-1}$$

\end{document}


If you don't plan to use \breve as a math accent it could be simplified, but it's better to have an alias \mbreve available. The code will redefine \breve as teubner does.

Thanx to the incredibly quick answer of daleif i found that the conflict is between teubner and fourier packages. But the issue is not commutative. This order of package call will compile but with the brackets issue reported:

\documentclass{article}

\usepackage[polutonikogreek, italian, english]{babel}

\usepackage{fourier}
\usepackage{teubner}

\begin{document}

$$\label{taus} \tau_e=\left(\frac{N_r\sigma_e}{v_{th}}\right)^{-1}$$

\end{document}


If we invert the order in which the packages are called it won't compile:

\documentclass{article}

\usepackage[polutonikogreek, italian, english]{babel}

\usepackage{teubner}

\usepackage{fourier}

\begin{document}

$$\label{taus} \tau_e=\left(\frac{N_r\sigma_e}{v_{th}}\right)^{-1}$$

\end{document}


giving an error because in fourier style command \breve finds an already defined one.

The issue is now solved by removing one of the two packages.