I would like unnumbered sections (more specifically unnumbered subsubsections) to appear in the table of contents, indented to their appropriate depth (i.e. as if they were numbered). I am using the amsbook document class.
Note: this issue is solved for non-ams document classes in the question how to make unnumbered sections aligned in table of contents? and for koma-script classes elsewhere, but as far as I can tell has not been addressed for ams classes.
A combination of this and this answer seems to work:
\documentclass{amsbook}
\begin{document}
\tableofcontents
\section{section A}
\section*{%
\for{toc}{\protect\hphantom{\numberline{\thesection}}section B}%
\except{toc}{section B}%
}
\section{section C}
\end{document}
Update
After checking the documentation for amsclass I found that \tocsection (which is also used for sub- and subsubsections) is defined as \indentlabel{\@ifnotempty{#2}{\ignorespaces#1 #2.\quad}}#3}. Therefore, the following quite easy set up should actually work:
\documentclass{amsbook}
\begin{document}
\setcounter{tocdepth}{3}
\tableofcontents
\section{section A}
\section*{%
\for{toc}{\protect\hphantom{\thesection.\quad}section B}%
\except{toc}{section B}%
}
\subsection{subsection 1}
\subsection*{%
\for{toc}{\protect\hphantom{\thesubsection.\quad}subsection 2}%
\except{toc}{subsection 2}%
}
\subsubsection{subsubsection a}
\subsubsection*{%
\for{toc}{\protect\hphantom{\thesubsubsection.\quad}subsubsection b}%
\except{toc}{subsubsection b}%
}
\subsubsection{subsubsection c}
\end{document}
The counters \thesection, \thesubsection and \thesubsubsection hold the value of the section, subsection or subsubsection before, in case of being the first entry, it is just zero. Thus, it should work even if there the very first entry is numberless.
