# Restatable numbering

\documentclass[11pt, oneside]{article}
\pagestyle{plain}

\usepackage{amsfonts,amssymb,amsmath,amsthm,amstext}
\newtheorem{theorem}{Theorem}[section]
\newtheorem{proposition}[theorem]{Proposition}
\usepackage{thmtools}
\usepackage{thm-restate}

\begin{document}
\section{Equations}
\begin{restatable}{theorem}{xyz}
$a = b = c.$
\end{restatable}

\begin{restatable}{proposition}{ab}
Let $a = b.$ Then $b = a.$
\end{restatable}

\section{The same equations}

New theorem.
\begin{theorem}
$a \neq d.$
\end{theorem}
Old theorems.

\xyz*
\ab*
\end{document}


I am using a restatable environment to repeat theorems. This works fine for {theorem}, but not for {proposition}. I would like to have the same numbering when restating a proposition (just like it happens for theorem).

Any help would be greatly appreciated, thank you.

First load packages, then do the settings.

\documentclass[11pt, oneside]{article}

\usepackage{amsmath,amssymb,amsthm}
\usepackage{thmtools}
\usepackage{thm-restate}

\newtheorem{theorem}{Theorem}[section]
\newtheorem{proposition}[theorem]{Proposition}

\pagestyle{plain}

\begin{document}

\section{Equations}
\begin{restatable}{theorem}{xyz}
$a = b = c.$
\end{restatable}

\begin{restatable}{proposition}{ab}
Let $a = b.$ Then $b = a.$
\end{restatable}

\section{The same equations}

New theorem.

\begin{theorem}
$a \neq d.$
\end{theorem}

Old theorems.

\xyz*

\ab*

\end{document}


By the way, amstext is loaded automatically by amsmath and amsfonts by amssymb. I left \pagestyle{plain} even if it's redundant in order to show how to do declarations and setting.

• Thank you, this worked out nicely. Commented May 30, 2021 at 10:13