restate an equation

Question

I know the restatable environment from the packages thm-restate combined with thmtools, which allows to formulate theorems that can be restated later in the document.

Now I am wondering, if there is a similar solution for equations like equation, align, etc.. I have already tried to just reuse that restatable environment for equations, but as expected I got an error.

I have already found "solutions" that suggestion to copy the content and tag the reference number. However, this seems to be a stopgap.

Have you tried using the cleveref package with the mathtools package to get the result? — Rachel Bond, Jul 19 '23 at 12:01
I work with cleveref and mathtools, but I don't know what you mean. Can you be a little bit more specific? To which macro are you referring to? — Nathanael Skrepek, Jul 19 '23 at 12:10
Related: https://tex.stackexchange.com/questions/406984/call-repeat-duplicate-equation-based-on-label — Steven B. Segletes, Aug 29 '23 at 03:42

mbert · Answer 1 · 2023-08-29T03:31:16.210

The code below provides a command \NewSavedEnvironment{<new-envname>}{<orig-envname>} that defines an environment with syntax

\begin{<new-envname>}{customid}
\end{<new-envname>}

whose contents can be restated with \customid*.

\documentclass{article}
\usepackage{thmtools,amsmath}
\newenvironment{donothing}{}{}
\NewDocumentCommand{\NewSavedEnvironment}{m m}{
    \NewDocumentEnvironment{#1}{m +b}{%
        \begin{restatable}{donothing}{##1}
        \begin{#2}
        ##2
        \end{#2}
        \end{restatable}%
        }{\unskip\ignorespacesafterend}
    }
\NewSavedEnvironment{savedequation}{equation}
\NewSavedEnvironment{savedalign}{align}
\begin{document}
\begin{savedequation}{somename} \label{mylab}
\sum_i a_i
\end{savedequation}
\begin{savedalign}{anothername}
f: X &\to Y \
x &\mapsto n\cdot x
\end{savedalign}
\somename*
\anothername*
\ref{mylab}
\end{document}

If you want to use this for environments that don't use the equation counter, see this answer.

restate an equation

1 Answers1