我的 MWE：
\documentclass[12pt]{amsbook}
\usepackage{amsbooka}
\usepackage{hyperref}
\pdfstringdefDisableCommands{%
\let\enspace\empty % this causes the warning for \kern
\let\noindent\empty % this causes the warning for \indent
}
\title{Hello}
\author{Just Me}
\begin{document}
\maketitle
\tableofcontents
\part{Commutative algebra}
\chapter{Some properties about the radical \author{Me Again}}
It's like, woah!
\end{document}
我收到错误：
Package hyperref Warning: Token not allowed in a PDF string (PDFDocEncoding):
(hyperref) removing `\<def>-command' on input line 19.
[5] [6]
Chapter 1
./mwe.tex:21: TeX capacity exceeded, sorry [input stack size=5000].
\MakeUppercase #1->\protect \MakeUppercase
{#1}
l.21 ...rties about the radical \author{Me Again}}
./mwe.tex:21: ==> Fatal error occurred, no output PDF file produced!
Transcript written on mwe.log.
（这些行会\pdfstringdefDisableCommands抑制一些超链接警告，但不会抑制上面的警告。）
如果我删除该amsbooka包，它就可以正常工作，但我的文档需要它（以允许每个章节都有自己的作者）。但也许这是一条线索？