我已经为此困扰了好几个小时。问题是我使用 overleaf 在线编译器完成了一篇论文的撰写。它编译时出现一个错误，但按预期生成了 pdf。错误消息如下所示：
The compiler is having trouble understanding a command you have used.
Check that the command is spelled correctly. If the command is part of a
package, make sure you have included the package in your preamble using
\usepackage{...}.
Learn more
l.640 ...lle, A.~Beygelzimer, F.~d\textquotesingle
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.
现在，当我尝试将论文提交给 arXiv 时，它根本无法在那里编译，也没有生成任何 pdf。错误消息是：
(/texlive/2020/texmf-dist/tex/latex/amsfonts/umsb.fd)
(/texlive/2020/texmf-dist/tex/latex/microtype/mt-msb.cfg)
! Missing $ inserted.
<inserted text>
$
l.79
?
>! Emergency stop.
<inserted text>
$
l.79
>! ==> Fatal error occurred, no output PDF file produced!
Transcript written on template.log.
[verbose]: pdflatex 'template.tex' failed.
[verbose]: Removing (La)TeX AUX file called 'template.out' (1613676344 >= 1613676343)
[verbose]: Removing (La)TeX AUX file called 'template.aux' (1613676344 >= 1613676343)
[verbose]: 'htex' is not a valid TeX format; will ignore.
[verbose]: TEXMFCNF is unset.
[verbose]: ~~~~~~~~~~~ Running tex for the first time ~~~~~~~~
[verbose]: Running: "(export HOME=/tmp PATH=/texlive/2020/bin/arch:/bin; cd /submissions/3608959/ && tex 'template.tex' < /dev/null)" 2>&1
[verbose]: This is TeX, Version 3.14159265 (TeX Live 2020) (preloaded format=tex)
(./template.tex
! Undefined control sequence.
l.1 \documentclass
{article}
> ?! Emergency stop.
l.1 \documentclass
{article}
No pages of output.
Transcript written on template.log.
[verbose]: tex 'template.tex' failed.
[verbose]: We failed utterly to process the TeX file 'template.tex'
[error]: Unable to sucessfully process tex files.
*** AutoTeX ABORTING ***
是否可以根据这些消息找到一些有关错误的线索？该文档很长，大约 12000 个字，因此我发现很难逐字逐句地阅读整个文档。任何帮助都非常感谢，
提前致谢！如果我应该发布任何其他可能有用的信息，请告诉我。