# Numbering subsections in one section only

I have a document in which I generally do not want to number the chapters, sections and subsections. Only one section should contain roman numbered subsections, how do I achieve that? I tried

\documentclass{report}
\setcounter{secnumdepth}{-1}

\begin{document}

\chapter{mwe}
\section{unnumbered subsections}
\subsection{unnumbered}

\section{roman numbered subsections}
\setcounter{secnumdepth}{2}
\renewcommand{\thesubsection}{\textnormal{\roman{subsection}}.}

\subsection{roman one}
\subsection{roman two}
\end{document}


However, this gives me an error at the \section{roman one} stating: Missing number treating as zero. Any suggestions for correction or ideas on alternative approaches?

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The example gives no error, only with article before the edit. However, you should change the base value of secnumdepth from 0 to -1, see my answer. – Stefan Kottwitz Oct 31 '11 at 9:21
@user7091: There's no need to edit the titles of your questions to inclue keyword |: That's what the tags are for, they get shown directly underneath the question title on the main page. – Jake Nov 1 '11 at 7:09

If you change the document class from article to book or report, your document works without error. The code in your question uses the \chapter command which is undefined in the article class. Try:

\documentclass{book}
\setcounter{secnumdepth}{-1}
\begin{document}
\tableofcontents
\chapter{mwe}
\section{unnumbered subsections}
\subsection{unnumbered}
\section{roman numbered subsections}
\setcounter{secnumdepth}{2}
\renewcommand{\thesubsection}{\textnormal{\roman{subsection}}.}
\subsection{roman one}
\subsection{roman two}
\setcounter{secnumdepth}{-1}
\chapter{Second chapter}
\section{unnumbered subsections}
\subsection{unnumbered}
\end{document}


Sometimes it's good to use \addtocounter instead of \setcounter, so you could raise or lower the numbering level without using the absolute value.

Also, as you can see, I used the counter value -1 for not numbering chapters, instead of 0.

In general, I think it's a bit inconsistent to change the numbering depth within a document.

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I identified the real problem and posted it here. Thanks for your efforts – D.Roepo Oct 31 '11 at 19:23

Instead of messing manually with the counters, try the starred versions of the sectioning commands, they exclude numbering (and the entry in the table of contents, for that matter):

\documentclass{article}

\begin{document}

\section*{unnumbered subsections}
\subsection*{unnumbered}

\section*{roman numbered subsections}
\renewcommand{\thesubsection}{\textnormal{\roman{subsection}}.}

\subsection{roman one}
\subsection{roman two}
\end{document}


Edit: If you want to include the starred sections in the ToC again, please read up the procedure in Centering \section* and adding them to the ToC.

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His original code works now because he changed from article to report. report has support for chapters where article does not. – Roelof Spijker Oct 31 '11 at 9:20
Yes it does. I wasn't aware that the problem lay elsewhere. If interested, see here. – D.Roepo Oct 31 '11 at 19:24