Understanding Amsthm and Pandoc

Oct 13, 2025 by wbrum.org 29 views

Introduction

When working with LaTeX documents, it's common to use both numbered theorems and equations to present mathematical concepts. However, when converting these documents to HTML using Pandoc, it can be challenging to maintain cross-references to both types of elements. In this article, we'll explore how to simultaneously cross-reference numbered Amsthm theorems and numbered equations using Pandoc for LaTeX to HTML conversion.

Understanding Amsthm and Pandoc

What is Amsthm?

Amsthm is a popular LaTeX package used for typesetting mathematical theorems, lemmas, and proofs. It provides a flexible way to define and number these elements, making it easier to organize and reference mathematical content.

What is Pandoc?

Pandoc is a universal document converter that can convert documents written in various markup languages, including LaTeX, to HTML, Markdown, and other formats. It's a powerful tool for converting LaTeX documents to HTML, allowing for math rendering via MathJax or MathML.

Cross-Referencing Numbered Amsthm Theorems and Equations

To cross-reference numbered Amsthm theorems and equations using Pandoc, you'll need to use the following steps:

Step 1: Define Numbered Amsthm Theorems and Equations

First, you'll need to define your numbered Amsthm theorems and equations in your LaTeX document using the amsthm package. Here's an example:

\documentclass{article}
\usepackage{amsthm}
\usepackage{amsmath}

\newtheorem{theorem}{Theorem}[section]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{corollary}[theorem]{Corollary}

\begin{document}

\section{Introduction}

\begin{theorem}\label{thm:example}
This is an example theorem.
\end{theorem}

\begin{equation}\label{eq:example}
x^2 + y^2 = z^2
\end{equation}

\end{document}

Step 2: Use Pandoc to Convert LaTeX to HTML

Next, you'll need to use Pandoc to convert your LaTeX document to HTML. You can do this using the following command:

pandoc input.tex -o output.html

Step 3: Configure Pandoc to Cross-Reference Numbered Amsthm Theorems and Equations

To configure Pandoc to cross-reference numbered Amsthm theorems and equations, you'll need to use the following options:

--mathjax: This option tells Pandoc to use MathJax for math rendering.
--mathml: This option tells Pandoc to use MathML for math rendering.
--filter pandoc-cite: This option tells Pandoc to use the pandoc-cite filter to cross-reference citations.
--filter pandoc-crossref: This option tells Pandoc to use the pandoc-crossref filter to cross-reference numbered Amsthm theorems and equations.

Here's an example of how to use these options:

pandoc input.tex --mathjax --mathml --filter pandoc-cite --filter pandoc-crossref -o output.html

Step 4: Use the `pandoc-crossref` Filter to Cross-Reference Numbered Amsthm Theorems and Equations

The pandoc-crossref filter is a custom filter that allows you to cross-reference numbered Amsthm theorems and equations using Pandoc. To use this filter, you'll need to create a custom filter file that defines the cross-referencing rules.

Here's an example of how to create a custom filter file:

\documentclass{article}
\usepackage{amsthm}
\usepackage{amsmath}

\newtheorem{theorem}{Theorem}[section]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{corollary}[theorem]{Corollary}

\begin{document}

\section{Introduction}

\begin{theorem}\label{thm:example}
This is an example theorem.
\end{theorem}

\begin{equation}\label{eq:example}
x^2 + y^2 = z^2
\end{equation}

\end{document}

You can then use the following command to apply the custom filter:

pandoc input.tex --mathjax --mathml --filter pandoc-cite --filter pandoc-crossref -o output.html

Conclusion

In this article, we've explored how to simultaneously cross-reference numbered Amsthm theorems and numbered equations using Pandoc for LaTeX to HTML conversion. By following the steps outlined in this article, you can create custom filter files that define the cross-referencing rules for your LaTeX documents. This allows you to maintain cross-references to both types of elements, making it easier to organize and reference mathematical content.

Future Work

In the future, we plan to expand the pandoc-crossref filter to support additional features, such as:

Support for multiple theorem environments
Support for multiple equation environments
Support for custom cross-referencing rules

We also plan to improve the documentation for the pandoc-crossref filter, making it easier for users to create custom filter files.

References

[1] "Amsthm Package Documentation" (2019)
[2] "Pandoc User Guide" (2020)
[3] "Pandoc-Crossref Filter Documentation" (2020)

Appendix

Here is an example of how to use the pandoc-crossref filter to cross-reference numbered Amsthm theorems and equations:

\documentclass{article}
\usepackage{amsthm}
\usepackage{amsmath}

\newtheorem{theorem}{Theorem}[section]
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{corollary}[theorem]{Corollary}

\begin{document}

\section{Introduction}

\begin{theorem}\label{thm:example}
This is an example theorem.
\end{theorem}

\begin{equation}\label{eq:example}
x^2 + y^2 = z^2
\end{equation}

\end{document}

You can then use the following command to apply the custom filter:

pandoc input.tex --mathjax --mathml --filter pandoc-cite --filter pandoc-crossref -o output.html

Q: What is the purpose of the `pandoc-crossref` filter?

A: The pandoc-crossref filter is a custom filter that allows you to cross-reference numbered Amsthm theorems and equations using Pandoc. It provides a way to define custom cross-referencing rules for your LaTeX documents.

Q: How do I use the `pandoc-crossref` filter?

A: To use the pandoc-crossref filter, you'll need to create a custom filter file that defines the cross-referencing rules for your LaTeX document. You can then use the following command to apply the custom filter:

pandoc input.tex --mathjax --mathml --filter pandoc-cite --filter pandoc-crossref -o output.html

Q: What are the benefits of using the `pandoc-crossref` filter?

A: The pandoc-crossref filter provides several benefits, including:

Improved cross-referencing: The filter allows you to cross-reference numbered Amsthm theorems and equations, making it easier to organize and reference mathematical content.
Customizable cross-referencing rules: The filter provides a way to define custom cross-referencing rules for your LaTeX documents, allowing you to tailor the behavior of the filter to your specific needs.
Easy to use: The filter is easy to use, and requires minimal configuration to get started.

Q: Can I use the `pandoc-crossref` filter with other Pandoc filters?

A: Yes, you can use the pandoc-crossref filter with other Pandoc filters. The filter is designed to be compatible with other Pandoc filters, and can be used in conjunction with filters such as pandoc-cite and pandoc-mathjax.

Q: How do I troubleshoot issues with the `pandoc-crossref` filter?

A: If you encounter issues with the pandoc-crossref filter, you can try the following troubleshooting steps:

Check the filter configuration: Make sure that the filter configuration is correct, and that the filter is being applied correctly.
Check the LaTeX document: Make sure that the LaTeX document is correctly formatted, and that the numbered Amsthm theorems and equations are correctly defined.
Check the Pandoc version: Make sure that you are using the latest version of Pandoc, and that the filter is compatible with your version of Pandoc.

Q: Can I customize the behavior of the `pandoc-crossref` filter?

A: Yes, you can customize the behavior of the pandoc-crossref filter by modifying the filter configuration. The filter provides a number of options that can be used to customize its behavior, including:

Custom cross-referencing rules: You can define custom cross-referencing rules for your LaTeX document using the pandoc-crossref filter.
Custom filter configuration: You can customize the filter configuration to suit your specific needs.

Q: How do I get started with the `pandoc-crossref` filter?

A: To get started with the pandoc-crossref filter, you'll need to:

Install Pandoc: Make sure that you have Pandoc installed on your system.
Install the pandoc-crossref filter: You can install the pandoc-crossref filter using the following command:

cabal install pandoc-crossref

Create a custom filter file: Create a custom filter file that defines the cross-referencing rules for your LaTeX document.
Apply the filter: Apply the filter to your LaTeX document using the following command:

pandoc input.tex --mathjax --mathml --filter pandoc-cite --filter pandoc-crossref -o output.html

Conclusion

In this Q&A article, we've covered some of the most frequently asked questions about the pandoc-crossref filter. We've discussed the purpose and benefits of the filter, as well as how to use it and troubleshoot issues. We've also covered how to customize the behavior of the filter, and how to get started with it.