# Number subsections and subsubsections, but not sections

I'm working on an article and I don't want to number my sections. However, I do want my subsections and subsubsections to be numbered. Right now my document has this numbering, but the 0 in 0.X.Y should not be there. How can I fix that?

Currently:
Section
0.1 subsection
0.2 subsection
0.2.1 subsubsection
0.3 subsection

Should be:
Section
1. subsection
2. subsection
2.1 subsubsection
3. subsection


This is my code:

\documentclass{article}

\begin{document}

\section*{Section}

\subsection{subsection}

\subsection{subsection}

\subsubsection{subsubsection}
blah
\subsection{subsection}

\end{document}


PS: I did search a on the web and found a lot on this topic, but not a solution to this particular thing.

-
What should happen after a 2nd \section*? Should the numbering start again at 1 or should it continue? –  knut Dec 5 '11 at 21:39

If you're interested in printing \section{<heading>} in a similar way that \section*{<heading>} would print (that is, flush left and not indented), then titlesec provides an easy interface:

\documentclass{article}
\usepackage{titlesec}% http://ctan.org/pkg/titlesec
\titleformat{\section}%
[hang]% <shape>
{\normalfont\bfseries\Large}% <format>
{}% <label>
{0pt}% <sep>
{}% <before code>
\renewcommand{\thesection}{}% Remove section references...
\renewcommand{\thesubsection}{\arabic{subsection}}%... from subsections
\begin{document}

\section{First section}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.

\subsection{First subsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.

\subsection{Second subsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.

\subsubsection{First subsubsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.

\subsection{Last subsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.

\section{Second section}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.

\subsection{First subsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.

\end{document}​


This just sets the label separator between the section number and title to 0pt, as well as not printing the number. \normalfont\bfseries\Large is the default formatting for article.

-

Does this works for you:

\documentclass{article}

\begin{document}

\part*{Section}

\section{subsection}

\section{subsection}

\subsection{subsubsection}
blah
\section{subsection}

\end{document}


Or is there a special reason, why you need sections as sections and subsections as subsection?

Alternative:

\documentclass{article}

\renewcommand{\thesection}{}
\renewcommand{\thesubsection}{\arabic{subsection}}

\begin{document}

\section{Section}

\subsection{subsection}

\subsection{subsection}

\subsubsection{subsubsection}
blah
\subsection{subsection}

\section{Section 2}

\subsection{subsection 2}
This subsection starts again with 1.

\end{document}

-
That does the job, but the size is rather large now. Can you tell me how to keep it the same size as the sections? Thanks :) –  Tony Dec 5 '11 at 14:54
I added a version with redefinition of thesection. –  knut Dec 5 '11 at 15:02
Thanks a lot for the "Alternative" version! :D –  Tony Dec 5 '11 at 15:03
This will not restart the numbering of the \subsections after the next \section*. –  Ulrike Fischer Dec 5 '11 at 15:21
You are right - but it works with \section. I change my answer. –  knut Dec 5 '11 at 19:16

Note: I rewrote this answer significantly after becoming aware of Ulrike Fisher's comment to @knut's answer.

There are two steps that need to be taken. The first, straightforward step consists of redefining the \thesubsection macro. The second, less obvious step involves a redefinition of the LaTeX internal macro \@seccntformat, as is explained in the book The LaTeX Companion, 2nd ed. The following MWE applies both steps:

\documentclass{article}

\renewcommand{\thesubsection}{\arabic{subsection}}
\makeatletter
\def\@seccntformat#1{\@ifundefined{#1@cntformat}%
{\csname #1@cntformat\endcsname}}%    enable individual control
\newcommand\section@cntformat{}
\makeatother

\begin{document}
\section{First Section}
\subsection{First subsection}
\subsection{Second subsection}
\subsubsection{First subsubsection}
\subsection{Third subsection}
\section{Second Section}
\subsection{A new subsection}
\end{document}


-
But without the redefinition of \thesection you still get a numbered section. See also my answer. –  knut Dec 5 '11 at 19:14
I understand. Then you have the same problem Ulrike mentioned: This will not restart the numbering of the \subsections after the next \section* - but there is no information in the question, what's needed in this case. –  knut Dec 5 '11 at 21:38
@knut: I just noticed the comment by Ulrike Fisher to your answer. She's right about having to use \section rather than \section*, as otherwise subsection numbers won't get reset in a new section. As my (now thoroughly revised) answer that's based on some code from The LaTeX Companion shows, what's really needed to solve the OP's challenge is both a redefinition of \@seccntformat and a new macro, \section@cntformat -- set here to {}. Interestingly, it is not necesssary to set \thesection to something like {}. Whew, this was a lot harder than it looked like at first! –  Mico Dec 6 '11 at 0:24