numberingtheorems
I wish to number my theorems within subsections as
Theorem 1
Theorem 2
Theorem 3
…
And only reset it back to 1 when I have a new subsection.
So I have a subsection within a section, and within the subsection I have several theorems, which are normally numbered section.subsection.theoremnumber.
But I want it just to be Theorem 1, Theorem 2, Theorem 3, etc until the end of the subsection, and in the next subsection, reset it back to Theorem 1, Theorem 2, etc.
How can I do this?
In LaTeX, “subcounters” are only reset when the counter is incremented by a \stepcounter. They are not reset when the counter is changed in any other way (e.g. via \setcounter or TeX commands).
The \section increments the section counter and thus sets the subsection counter to 0. But this does not reset the theorem counter. Only the next \subsection (which increments the subsection counter) resets the theorem counter.
I guess the easiest (or at least safest; see the comments) workaround is to simply add the theorem counter to the reset list for the section counter:
\makeatletter
\@addtoreset{theorem}{section}
\makeatother
Similar to the solution at this question and section 3 of the amsthm documentation:
\documentclass[11pt,a4paper]{report}
\usepackage{amsthm}
\theoremstyle{plain}
\newtheorem{thm}{Theorem}[chapter] % reset theorem numbering for each chapter
\theoremstyle{definition}
\newtheorem{defn}[thm]{Definition} % definition numbers are dependent on theorem numbers
\newtheorem{exmp}[thm]{Example} % same for example numbers
\newcommand{\chaptercontent}{
\section{Basics}
\begin{defn}Here is a new definition.\end{defn}
\begin{thm}Here is a new theorem.\end{thm}
\begin{thm}Here is a new theorem.\end{thm}
\begin{exmp}Here is a good example.\end{exmp}
\subsection{Some tips}
\begin{defn}Here is a new definition.\end{defn}
\section{Advanced stuff}
\begin{defn}Here is a new definition.\end{defn}
\subsection{Warnings}
\begin{defn}Here is a new definition.\end{defn}
}
\begin{document}
\tableofcontents
\part{Addition and Subtraction}
\chapter{Addition} \chaptercontent
\chapter{Subtraction} \chaptercontent
\part{Multiplication and Division}
\chapter{Multiplication} \chaptercontent
\chapter{Division} \chaptercontent
\end{document}
Best Answer
Specify the theorem to renew with every
\subsection, and then remove thesubsectioncounter from the theorem counter representation: