Theorem environment numbered according to subsection

Question

I was wondering if there was a way to modify the theorem environment so that it interacted with sections/subsections as follows:

\section{}
\subsection{}
\begin{ex} Whatever
\end{ex}

\begin{ex}Whatever
\end{ex}



\subsection{}

\begin{ex} Whatever

\end{ex}

Would output something like

1
1.1

Exercise 1.1.1


Exercise 1.1.2



1.2

Exercise 1.2.1

Where \begin{ex} is just an environment for an "exercise".

Sounds very doable :) could you turn your snippet into a complete MWE :) — cmhughes, Dec 20 '12 at 03:25
Related: http://tex.stackexchange.com/questions/28333/continuous-v-per-chapter-section-numbering-of-figures-tables-and-other-docume — lockstep, Dec 20 '12 at 10:49

score 8 · Answer 1 · edited Dec 20 '12 at 12:35

8

You can use the built-in feature for theorem numbering:

\documentclass{article}

\usepackage{amsthm} % not necessary

\newtheorem{ex}{Exercise}[subsection]

\begin{document}

\section{}

\subsection{}

\begin{ex}
Whatever
\end{ex}

\begin{ex}
Whatever
\end{ex}

\subsection{}

\begin{ex}
Whatever
\end{ex}

\end{document}

edited Dec 20 '12 at 12:35

Andrew Swann

95,762

answered Dec 20 '12 at 08:09

yo'

51,322

2

This is a standard feature, not only of amsthm. – egreg Dec 20 '12 at 08:37
@egreg And there exists \newtheorem without amsthm? – yo' Dec 20 '12 at 08:49
2

Yes, of course; amsthm and the similar ntheorem just add to the kernel functionality. – egreg Dec 20 '12 at 08:50

Theorem environment numbered according to subsection

1 Answers1