# Book: Chapter/Section/Subsection Numbering

I'm new to LaTeX but want to try to tex my Linear Algebra lecture. My lecturer is using the following structure:

Chapter 0: Basics

• § 1 Sets
• Def. 1.1: Some definition
• Def. 1.2: Some definition
• Pro. 1.3: Some proposition
• Exm. 1.4: Some example
• § 2 Other section
• § 3 Other section
• Def. 3.1: Some definition
• Def. 3.2: Some definition
• Pro. 3.3: Some proposition
• Exm. 3.4: Some example
• § 4 Other section

Chapter 1: Groups, Rings and Fields

• § 5 Groups
• Def. 5.1: Some definition
• ...
• § 6 Rings

The structure in words:

• Chapters
• Numbered (starting from 0)
• Section (in Chapters)
• Numbered
• not affected by chapter numbered
• don't reset when a new chapter is started
• Subsections (Definitions, Examples, Propositions)
• Numbered with current Section-Number as prefix
• Reset each new section

It would be great to be able to write something like this:

\documentclass{book}
...

\begin{document}

\chapter{Basics}

\section{Sets}
\subsection{Def. :}
Some definition.

\subsection{Example :}
Some example.

\section{NewSection}
....

\chapter{Groupds, Rings, Fields}

\section{Groups}

\subsection{Def. :}
Some definition

...

\end{document}


The behaviour differs from the desired behaviour in the following ways: Chapter-Numbering starts at 1, Section-Numbering reset each chapter. Sections don't start with a §-symbol automatically. Subsections contain chapter/section and subsection numbers.

How can I get my desired layout?

• Before elaborating in detail: How to number equations, tables, figures? What about subsections that are neither definitions nor propositions nor examples? What about definitions, propositions and examples that occur in other levels of sectioning than subsection? Nov 23, 2016 at 4:45

In case of numbering sections independent from chapters, the question will be raised how to number definitions/propositions/examples that are placed in a chapter but are not be placed in a section?

E.g.:

Chapter 0 Basics
1 Elements
2 Combinations
Def. 2.1: Some definition
Def. 2.2: Some definition
Pro. 2.3  Some proposition
Exm. 2.4: Some Example
2.1 Permutations
2.2 Sets
Def. 2.2.1: Some definition
Def. 2.2.2: Some definition
Pro. 2.2.3  Some proposition
Exm. 2.2.4: Some Example
Chapter 1 Groups
Def. <???>1: Some definition
Pro. <???>2  Some proposition
Exm. <???>3: Some Example
3 Groups
Def. 3.1: Some definition
Pro. 3.2  Some proposition
Exm. 3.3: Some Example
Chapter 2 Rings and Fields
Def. <???>1: Some definition
Pro. <???>2  Some proposition
Exm. <???>3: Some Example
4 Rings
5 Fields


How should definitions/propositions/examples in Chapter 1 be named?
They don't belong to section 2. And they don't belong to section 3.

How should definitions/propositions/examples in Chapter 2 be named? They don't belong to section 3. And they don't belong to section 4.

I suggest <???>=<chapter>/<definition/proposition/example number> in these cases:

Chapter 0 Basics
1 Elements
2 Combinations
Def. 2.1: Some definition
Def. 2.2: Some definition
Pro. 2.3  Some proposition
Exm. 2.4: Some Example
2.1 Permutations
2.2 Sets
Def. 2.2.1: Some definition
Def. 2.2.2: Some definition
Pro. 2.2.3  Some proposition
Exm. 2.2.4: Some Example
Chapter 1 Groups
Def. 1/1: Some definition
Pro. 1/2  Some proposition
Exm. 1/3: Some Example
3 Groups
Def. 3.1: Some definition
Def. 3.2: Some definition
Pro. 3.3  Some proposition
Exm. 3.4: Some Example
Chapter 2 Rings and Fields
Def. 2/1: Some definition
Pro. 2/2  Some proposition
Pro. 2/3  Some proposition
Exm. 2/4: Some Example
4 Rings
5 Fields


Another question is about the numbering of footnotes, tables, figures and equations.

I suggest numbering footnotes per chapter.
I suggest numbering tables, figures and equations per section as deeper sectioning-levels might have equally numbered definition/proposition/example-pendants.

I suggest handling the case of tables/figures/equations in a chapter but not in a section in the same way as definition/proposition/example in a chapter but not in a section, i.e. by prepending "/" to the corresponding number.

Yet another question:

Do you wish something like a separate List of definitions / List of propositions / List of examples.

I suggest not having a a separate List of definitions / List of propositions / List of examples.
These things require more crude hacking of the documentclass / of the book class.

\documentclass{book}
\usepackage{hyperref}
\makeatletter
\newcounter{TheoremElement}
\newcounter{sectionfake}
\begingroup
\def\tempa#1{\global\csname c@#1\endcsname\z@}%
\expandafter\endgroup\ifx\tempa\@stpelt
\expandafter\@firstoftwo\else\expandafter\@secondoftwo\fi
{%
\def\c@sectionfakehack\z@
}{%
\def\c@sectionfakehack\m@ne\stepcounter#1%
}%
{%
\let\c@sectionfake\c@sectionfake\stepcounter{sectionfake}%
}%
\renewcommand\cl@chapter{%
\@elt{sectionfake}%
\@elt{footnote}%
\@elt{equation}\@elt{figure}\@elt{table}%
\@elt{subsection}\@elt{subsubsection}%
\@elt{paragraph}\@elt{subparagraph}%
\@elt{TheoremElement}%
}%
\renewcommand\cl@section{%
\@elt{sectionfakehack}%<-the hack increments sectionfake instead of resetting
%  to zero whenever section is incremented via \stepcounter
\@elt{equation}\@elt{figure}\@elt{table}%
\@elt{subsection}\@elt{subsubsection}%
\@elt{paragraph}\@elt{subparagraph}%
\@elt{TheoremElement}%
}%
\renewcommand\cl@subsection{%
\@elt{subsubsection}%
\@elt{paragraph}\@elt{subparagraph}%
\@elt{TheoremElement}%
}%
\renewcommand\cl@subsubsection{%
\@elt{paragraph}\@elt{subparagraph}%
\@elt{TheoremElement}%
}%
\renewcommand\cl@paragraph{%
\@elt{subparagraph}%
\@elt{TheoremElement}%
}%
\renewcommand\cl@subparagraph{%
\@elt{TheoremElement}%
}%
\renewcommand*\cl@TheoremElement{}%
%
\newcommand\sectionfakefork{%
\ifnum\number\value{sectionfake}>0 %
\expandafter\@firstoftwo\else\expandafter\@secondoftwo\fi
}%
\newcommand\AllSectionLevelsArabic{%
\sectionfakefork
{%
\AllSectionLevelsArabicLoop{\AllSectionLevelsArabicLoop{%
\AllSectionLevelsArabicLoop{\AllSectionLevelsArabicLoop{%
\@firstoftwo{\arabic{section}.}%
}{subsection}.}{subsubsection}.%
}{paragraph}.}{subparagraph}.%
\@firstoftwo
}{%
\arabic{chapter}/%
}%
\arabic{TheoremElement}%
}%
\newcommand\AllSectionLevelsArabicLoop{%
#4{\ifnum\number\value{#2}>0 %
\expandafter\@firstoftwo\else\expandafter\@secondoftwo\fi
{#1\@secondoftwo\arabic{#2}#3}{#1#4}%
}{#1\@secondoftwo\arabic{#2}#3}%
}%
\newcommand\insertbehindnumber{%
#1\@insertbehimdnumber{#2}%
}%
\newcommand\@insertbehimdnumber{}%
\long\def\@insertbehimdnumber#1#2\endcsname{#2\endcsname#1}%
\renewcommand\theTheoremElement{\AllSectionLevelsArabic}
\newtheorem{definition}[TheoremElement]{\insertbehindnumber{Def.}{:}}%
\newtheorem{proposition}[TheoremElement]{\insertbehindnumber{Pro.}{:}}%
\newtheorem{example}[TheoremElement]{\insertbehindnumber{Exm.}{:}}%
\renewcommand\theequation{\sectionfakefork{\arabic{section}.}{\arabic{chapter}/}\arabic{equation}}%
\renewcommand\thetable{\sectionfakefork{\arabic{section}.}{\arabic{chapter}/}\arabic{table}}%
\renewcommand\thefigure{\sectionfakefork{\arabic{section}.}{\arabic{chapter}/}\arabic{figure}}%
\renewcommand\thesection{\protect\S\texorpdfstring{\protect\,}{ }\arabic{section}}%
\AtBeginDocument{%
% Remove the dot after chapter-numbers in headers of verso pages:
%\renewcommand*\chaptermark{%
%  \markboth{%
%    \MakeUppercase{%
%    }%
%  }{}%
%}%
% Remove the dot after sectioning-paragraph-numbers in headers of recto pages:
\renewcommand*\sectionmark{%
\markright{%
}%
}%
% Ensure uniqueness of hyperref' anchor names:
\renewcommand\theHsection{\arabic{section}}%
\renewcommand\theHTheoremElement{\AllSectionLevelsArabic}%
\renewcommand\theHequation{\sectionfakefork{\arabic{section}.}{\arabic{chapter}/}\arabic{equation}}%
\renewcommand\theHtable{\sectionfakefork{\arabic{section}.}{\arabic{chapter}/}\arabic{table}}%
\renewcommand\theHfigure{\sectionfakefork{\arabic{section}.}{\arabic{chapter}/}\arabic{figure}}%
\renewcommand\theHfootnote{\arabic{chapter}.\arabic{footnote}}%
}{%
\providecommand\texorpdfstring{#1}%
}%
}%
\makeatother

\setcounter{secnumdepth}{4}
\setcounter{tocdepth}{\value{secnumdepth}}
\usepackage[open,openlevel=\value{secnumdepth},atend,numbered]{bookmark}

\begin{document}
\tableofcontents

\setcounter{chapter}{-1}%

\chapter{Basics}

\begin{definition}
Some definition.
\end{definition}

\section{Sets}

\begin{definition}
\label{deflabel}Some definition.
\end{definition}

\begin{definition}
Some definition.
\end{definition}

\begin{proposition}
\label{proplabel}Some proposition.
\end{proposition}

\begin{example}
\label{exlabel}Some example.
\end{example}

\section{Other section}

\section{Other section}

\begin{definition}
Some definition.
\end{definition}

\begin{definition}
Some definition.
\end{definition}

\begin{proposition}
Some proposition.
\end{proposition}

\begin{example}
Some example.
\end{example}

\section{Other section}

\chapter{Groups, Rings and Fields}

\begin{definition}
\label{otherdeflabel}Some definition.
\end{definition}

\section{Groups}

\begin{definition}
Some definition.
\end{definition}

\subsection{SubGroups}

\begin{definition}
Some definition.
\end{definition}

\subsubsection{SubSubGroups}

\begin{definition}
\label{yetanotherdeflabel}Some definition.
\end{definition}

\section{Rings}

\cleardoublepage
\section{Testing referencing}

referencing a definition: \ref{deflabel}\\
referencing a proposition: \ref{proplabel}\\
referencing an example: \ref{exlabel}\\
referencing another definition: \ref{otherdeflabel}\\
referencing yet another definition: \ref{yetanotherdeflabel}
\end{document}

• Wow, thank you so much for the answer, but honestly I cannot really get through all of this. I'm very new to latex and don't know much of the \begingroup, \expandafter \@firstoftwo \sectionfakehack- things. Could you try to elaborate a little bit more step by step? Regarding your questions: Definitions/Examples/Propositions never occur outside of a section and shouldn't be included in the table of contents. No separate list is required... Nov 23, 2016 at 17:41