Feature request: shared numbering of environments

[thomaspcottrell]

As noted in Section 2.2.2 of Authoring Books with R Markdown, Bookdown does not support shared numbering between different environments (theorems, definitions, etc.). Is there any possibility of or plan to include this feature in the future? To my mind, this is an essential feature of good maths writing.

---

By filing an issue to this repo, I promise that

• I have fully read the issue guide at https://yihui.org/issue/.
• I have provided the necessary information about my issue.
  • If I'm asking a question, I have already asked it on Stack Overflow or RStudio Community, waited for at least 24 hours, and included a link to my question there.
  • If I'm filing a bug report, I have included a minimal, self-contained, and reproducible example, and have also included xfun::session_info('bookdown'). I have upgraded all my packages to their latest versions (e.g., R, RStudio, and R packages), and also tried the development version: remotes::install_github('rstudio/bookdown').
  • If I have posted the same issue elsewhere, I have also mentioned it in this issue.
• I have learned the Github Markdown syntax, and formatted my issue correctly.

I understand that my issue may be closed if I don't fulfill my promises.

[cderv]

For reference, with LaTeX, \newtheorem can take some options to control part of the numbering. (https://www.overleaf.com/learn/latex/theorems_and_proofs#Numbered_theorems.2C_definitions.2C_corollaries_and_lemmas) which the bookdown book document too
https://bookdown.org/yihui/bookdown/markdown-extensions-by-bookdown.html#theorems

Theorems are numbered by chapters by default. If there are no chapters in your document, they are numbered by sections instead. If the whole document is unnumbered (the output format option number_sections = FALSE), all theorems are numbered sequentially from 1, 2, …, N. LaTeX supports numbering one theorem environment after another, e.g., let theorems and lemmas share the same counter. This is not supported for HTML/EPUB output in bookdown. You can change the numbering scheme in the LaTeX preamble by defining your own theorem environments, e.g.,

\newtheorem{theorem}{Theorem}
\newtheorem{lemma}[theorem]{Lemma}

When bookdown detects \newtheorem{theorem} in your LaTeX preamble, it will not write out its default theorem definitions, which means you have to define all theorem environments by yourself. For the sake of simplicity and consistency, we do not recommend that you do this. It can be confusing when your Theorem 18 in PDF becomes Theorem 2.4 in HTML.

So shared numbering is possible for PDF output if you provide a all the theorem and proof definition in preamble.tex

Have you tried that ?

However, this won't work for non PDF output.

IMO this would not be trivial to implement.

[thomaspcottrell]

Thanks. Evidently I should have been more specific about what the problem was. I am specifically interested in being able to do this with html output. (I am writing lecture notes and legally required to provide them in an accessible format, so pdf is no good.) Thankfully, the problem has been solved by using ClavertonDown.

[cderv]

Thanks for sharing this formats. I did not know about it.
The referencing is there in the example https://bathmash.github.io/clavertondown/repeating-environments.html repo is there https://github.com/BathMASH/clavertondown

We welcome a PR if the solution found worth sharing in bookdown