[Tex/LaTex] How to reprint a theorem, proposition, etc. in its entirety

Question

I would like to prove all my theorems in the appendix. To do that, I would like to remind the readers what the theorem is, by reprinting it in the appendix.

However, I have not figured out a way to do this without directly copy and pasting. The the problem with copy and pasting is that the theorem number is completely off. Take for example:

Does anyone know how to deal with this problem elegantly?

\documentclass{article}
\usepackage[utf8]{inputenc}

\usepackage{amsthm}     
\setlength\parindent{0pt}
\theoremstyle{definition}
\newtheorem{definition}{Definition}[section]

\theoremstyle{thm}
\newtheorem{thm}{Theorem}[section]
\newtheorem{lem}{Lemma}[section]
\newtheorem{prop}{Proposition}[section]
\newtheorem{cor}{Corollary}[section]
\newtheorem{conj}{Conjecture}[section]
\newtheorem{claim}{Claim}[section]

\theoremstyle{remark}
\newtheorem{remark}{Remark}[section]
\newtheorem{example}{Example}[section]

\newcommand{\thmautorefname}{Theorem}
\newcommand{\propautorefname}{Proposition}
\newcommand{\lemautorefname}{Lemma}
\newcommand{\corautorefname}{Corollary}
\newcommand{\conjautorefname}{Conjecture}
\newcommand{\claimautorefname}{Claim}


\begin{document}


\section{Introduction}

\begin{thm}
We'd like to introduce the \bfseries{theorem of the universe}, the theorem says that $1+1 = 2$
\end{thm}
This is a remarkable theorem indeed!

\section{Appendix}
In the Appendix, we will prove theorem

We will reprint the theorem here:

\begin{thm}
We'd like to introduce the \bfseries{theorem of the universe}, the theorem says that $1+1 = 2$
\end{thm}

\begin{proof}
2 - 1 = 1. 
\end{proof}


\bibliographystyle{plain}
\bibliography{references}
\end{document}

Answer 1

The thmtools defines restatable theorems. Here is how it goes. B.t.w., the thm theorem style does not exist, as this is defined by thmtools. I suppose you meant the plain style. Also, I had to comment the autorefnames, as they're already defined by thmtools.

\documentclass{article}
\usepackage[utf8]{inputenc}

\usepackage{amsthm,thmtools}%
\setlength\parindent{0pt}
\theoremstyle{definition}
\newtheorem{definition}{Definition}[section]

\theoremstyle{plain}
\declaretheorem[name=Theorem, numberwithin=section]{thm}
\declaretheorem[name=Lemma, numberwithin=section]{lem}
\declaretheorem[name=Proposition, numberwithin=section]{prop}
\declaretheorem[name=Corollary, numberwithin=section]{cor}
\declaretheorem[name=Conjecture, numberwithin=section]{conj}
\declaretheorem[name=Claim, numberwithin=section]{claim}

\theoremstyle{remark}
\newtheorem{remark}{Remark}[section]
\newtheorem{example}{Example}[section]

%\newcommand{\thmautorefname}{Theorem}
%\newcommand{\propautorefname}{Proposition}
%\newcommand{\lemautorefname}{Lemma}
%\newcommand{\corautorefname}{Corollary}
%\newcommand{\conjautorefname}{Conjecture}
%\newcommand{\claimautorefname}{Claim}

\begin{document}

\section{Introduction}

\begin{restatable}{thm}{universe}
We'd like to introduce the \bfseries{theorem of the universe}, the theorem says that $1+1 = 2$
\end{restatable}
This is a remarkable theorem indeed!

\section{Appendix}
In the Appendix, we will prove theorem

We will reprint the theorem here:

\universe*

\begin{proof}
$ 2 - 1 = 1 $.
\end{proof}

\bibliographystyle{plain}
\bibliography{references}

\end{document}