On the website for LyX I posted a bug report:
https://www.lyx.org/trac/ticket/10607
The maintainers are unsure how to fix it and suggested I head to Stack Exchange.
In brief, for the “American Mathematical Society (AMS) Article" document class there is a bug which causes the titles atop the pages to display incorrectly. On Stack Exchange I found the following questions, which might be related:
How to turnoff 'language' field with biblatex?
MiKTeX 2.9, LyX 2.1, BibLaTeX: How do I suppress language after title field in references?
The maintainers for LyX would like to correct the error. If anyone knows what causes it, please spell it out. If more information is required, let me know.
test file from lyx trac:
%% LyX 2.1.5 created this file. For more info, see http://www.lyx.org/.
%% Do not edit unless you really know what you are doing.
\documentclass[letterpaper,oneside,english]{amsart}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\usepackage{amsthm}
\makeatletter
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% LyX specific LaTeX commands.
\pdfpageheight\paperheight
\pdfpagewidth\paperwidth
\providecommand{\LyX}{L\kern-.1667em\lower.25em\hbox{Y}\kern-.125emX\@}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Textclass specific LaTeX commands.
\numberwithin{equation}{section}
\numberwithin{figure}{section}
\makeatother
\usepackage{babel}
\begin{document}
\title{Results which are going to change the world}
\author{\LyX{} user}
\date{2 April 2017}
\begin{abstract}
in this paper we will test a bug in \LyX{}.
\end{abstract}
\maketitle
\pagebreak{}
\section{Introduction}
...
\pagebreak{}
\section{Body}
...
\pagebreak{}
\section{Conclusion}
...
\begin{thebibliography}{1}
\bibitem{key-1}...\end{thebibliography}
\end{document}
Thank you for your help. I figured out the cause of the bug. See the original posting for LyX.
.lyxfile nor the.texfile), so it's hard to say without more info. (And it doesn't usebiblatexfor bibliographies, so I don't think those questions are related.) Which LaTeX distribution have you got installed (TeX Live, MikTeX, MacTeX)? Have you updated it recently? Can you post the LaTeX log file? (In LyX 2.2.2 you can find that under Document --> LaTeX log, can't remember if it was elsewhere in LyX 2.1.) – Torbjørn T. May 23 '17 at 18:11\listfilesand show the log tex produces, you presumably have some local file being input somewhere. – David Carlisle May 23 '17 at 19:08amsartincorporatesamsthm(unless the lyx crew has changed something), so it's not necessary to load it separately. – barbara beeton May 26 '17 at 00:57