Why does this:




This is pdfTeX, Version 3.1415926-2.5-1.40.14 (TeX Live 2013)
 restricted \write18 enabled.
entering extended mode
LaTeX2e <2011/06/27>
Babel <3.9f> and hyphenation patterns for 78 languages loaded.
Document Class: report 2007/10/19 v1.4h Standard LaTeX document class

./coprod@mu.tex:3: LaTeX Error: Missing \begin{document}.

See the LaTeX manual or LaTeX Companion for explanation.
Type  H <return>  for immediate help.

l.3 ...ymbol{\coprod@}{\mathop}{largesymbols}{"60}

and what should I do to fix it?

Update: As the answers suggested, I'm missing \makeatletter and \makeatother. Adding them compiles to: enter image description here I would like: enter image description here How do I get that?

  • Your edit is really an entirely different question!
    – Joseph Wright
    Oct 9, 2014 at 7:26
  • 1
    What should be the purpose of \let\DOTSB\relax and of \let\slimits@\relax? You're simply trying to break amsmath. Regarding the missing symbol: the fonts available with mathptmx don't have a coproduct symbol. It's available if you say \usepackage{newtxtext,newtxmath} instead of \usepackage{mathptmx}.
    – egreg
    Oct 9, 2014 at 8:01
  • I've already started reading the documentation and will probably make a package replacement. Does that package have \imath and \jmath as well, by chance?
    – MickG
    Oct 9, 2014 at 10:43

2 Answers 2


Without a brace of \makeatletter/\makeatother, @ cannot be part of command names.

\DeclareMathSymbol …

seemed to work better for me (though I don't know what your intended result is – it compiled, at least).


I think you are missing \makeatletter before line 3 and \makeatother before \begin{document}. LaTeX tries to expand @-commands and so raise that error.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.