1

i'm using latex on a development version of ubuntu 20.04. in this environment, the babel and breqn packages generate error "! You can't use `the character ,' after \the." this did not happen before the upgrade from ubuntu 19.10. (apologies that i cannot be more specific.)

does anyone know a workaround?

\documentclass[a4paper, 12pt, reqno]{article}
\usepackage[english]{babel}
\usepackage{breqn}

\begin{document}

\title{Minimum Working Example}
\maketitle

This is a test\ldots
\begin{dmath}
    \Psi = 0.
\end{dmath}

\end{document}

"latex mwe-01.tex" generates:

This is pdfTeX, Version 3.14159265-2.6-1.40.20 (TeX Live 2019/Debian) (preloaded format=latex)
 restricted \write18 enabled.
entering extended mode
(./mwe-01.tex
LaTeX2e <2020-02-02> patch level 2
L3 programming layer <2020-02-14>
(/usr/share/texlive/texmf-dist/tex/latex/base/article.cls
Document Class: article 2019/12/20 v1.4l Standard LaTeX document class
(/usr/share/texlive/texmf-dist/tex/latex/base/size12.clo))
(/usr/share/texlive/texmf-dist/tex/generic/babel/babel.sty
(/usr/share/texlive/texmf-dist/tex/generic/babel/switch.def)
(/usr/share/texlive/texmf-dist/tex/generic/babel-english/english.ldf
(/usr/share/texlive/texmf-dist/tex/generic/babel/babel.def
(/usr/share/texlive/texmf-dist/tex/generic/babel/txtbabel.def))))
(/usr/share/texlive/texmf-dist/tex/latex/breqn/breqn.sty
(/usr/share/texlive/texmf-dist/tex/latex/l3kernel/expl3.sty
(/usr/share/texlive/texmf-dist/tex/latex/l3backend/l3backend-dvips.def))
(/usr/share/texlive/texmf-dist/tex/latex/amsmath/amsmath.sty
For additional information on amsmath, use the `?' option.
(/usr/share/texlive/texmf-dist/tex/latex/amsmath/amstext.sty
(/usr/share/texlive/texmf-dist/tex/latex/amsmath/amsgen.sty))
(/usr/share/texlive/texmf-dist/tex/latex/amsmath/amsbsy.sty)
(/usr/share/texlive/texmf-dist/tex/latex/amsmath/amsopn.sty))
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphicx.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/keyval.sty)
(/usr/share/texlive/texmf-dist/tex/latex/graphics/graphics.sty
(/usr/share/texlive/texmf-dist/tex/latex/graphics/trig.sty)
(/usr/share/texlive/texmf-dist/tex/latex/graphics-cfg/graphics.cfg)
(/usr/share/texlive/texmf-dist/tex/latex/graphics-def/dvips.def)))
(/usr/share/texlive/texmf-dist/tex/latex/breqn/flexisym.sty
(/usr/share/texlive/texmf-dist/tex/latex/breqn/cmbase.sym)
(/usr/share/texlive/texmf-dist/tex/latex/breqn/mathstyle.sty))
(/usr/share/texlive/texmf-dist/tex/latex/tools/calc.sty)) (./mwe-01.aux)

LaTeX Warning: No \author given.

! You can't use `the character ,' after \the.
\@elt #1->,#1,

l.13 \end{dmath}

? 
! Emergency stop.
\@elt #1->,#1,

l.13 \end{dmath}

No pages of output.
Transcript written on mwe-01.log.
Paul Schweinzer
  • 11
  • 1

1 Answers1

0

Welcome to TeX.SE. There is an important fragment

\let\oldcdot\cdot
\usepackage{breqn}
\let\cdot\oldcdot

of the very nice user @David Carlisle here into this link breqn: specifying the characters at which equations can be broken 

\documentclass[a4paper, 12pt, reqno]{article}
\usepackage[english]{babel}
\let\oldcdot\cdot
\usepackage{breqn}
\let\cdot\oldcdot
\begin{document}

\title{Minimum Working Example}
\maketitle

This is a test\ldots
\begin{dmath}
    \Psi = 0.
\end{dmath}

\end{document}

and your code work correctly.

enter image description here

Sebastiano
  • 54,118
  • thanks @Sebastiano! unfortunately, the error persists in my environment after inserting the suggested '\let\oldcdot\cdot \usepackage{breqn} \let\cdot\oldcdot' – Paul Schweinzer Apr 06 '20 at 18:24
  • @user762966 Don't worry. Have you done an update of your distribution of TeX-Live? I have seen that the date is 2020-02-02. – Sebastiano Apr 06 '20 at 19:50
  • 1
    thanks again, @Sebastiano: seems i cannot update with tlmgr on the beta image (probably only possible with the final ubuntu release). – Paul Schweinzer Apr 06 '20 at 20:13
  • @user762966 Have you seen? :) don't worry...surely there is a problem on your distribuition (I am not very expert). – Sebastiano Apr 06 '20 at 20:17