About counting in \newtheorems

Question

For all my \newtheorems i want the below counting:

when i have for example only a section, i want the counting starts and following the number of section. Next, if i have subsection i want the counting starts and following the number of subsection and so on. how can i do this?

I don't want all the newtheorems follow the "subsection" counting. I want this counting when i have subsection

Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. — Community, Oct 02 '23 at 16:22

score 1 · Answer 1 · answered Oct 02 '23 at 17:23

You seem to want something like this:

1 Section title A

Some text following.

1.1 Theorem. The statement of the theorem

Some text following.

1.2 Theorem. The statement of the theorem

Some text following.

1.1 Subsection title A

Some text following.

1.1.1 Theorem. The statement of the theorem

Some text following.

1.1.2 Theorem. The statement of the theorem

Some text following.

1.2 Subsection title B

1.2.1 Theorem. The statement of the theorem

2 Section title B

Some text following.

2.1 Theorem. The statement of the theorem

Some text following.

2.2 Theorem. The statement of the theorem

Here's the code.

\documentclass{article}
\usepackage{amsthm}
\newtheorem{theorem}{Theorem}[subsection]% theorem is reset at subsections
\counterwithin*{theorem}{section}% theorem is also reset at sections
\renewcommand{\thetheorem}{%
  \ifnum\value{subsection}>0
    % we're after \subsection
    \thesubsection
  \else
    % no \subsection came along yet
    \thesection
  \fi
  .\arabic{theorem}%
}
\begin{document}
\section{Section title A}
Some text following.
\begin{theorem}
The statement of the theorem
\end{theorem}
Some text following.
\begin{theorem}
The statement of the theorem
\end{theorem}
Some text following.
\subsection{Subsection title A}
Some text following.
\begin{theorem}
The statement of the theorem
\end{theorem}
\begin{theorem}
The statement of the theorem
\end{theorem}
\subsection{Subsection title B}
Some text following.
\begin{theorem}
The statement of the theorem
\end{theorem}
\section{Section title B}
Some text following.
\begin{theorem}
The statement of the theorem
\end{theorem}
Some text following.
\begin{theorem}
The statement of the theorem
\end{theorem}
\end{document}

Don't. Just use

\newtheorem{theorem}{Theorem}[section]

and your readers will be happier.

About counting in \newtheorems

1 Answers1