Math blocks are not rendered when delimiters are indented for list-item continuation

[MikeProjects]

🏷️ Discussion Type

Question

💬 Feature/Topic Area

Code Search and Navigation

Body

Hi, GitHub team, 👋

Thank you for the outstanding work on GitHub and for continuously improving the Markdown experience.

I found a rendering issue in GitHub Markdown when trying to keep a display math block logically inside a list item.

Problem summary

When a math delimiter is indented (to keep the block inside a bullet/list continuation), GitHub renders the math source as plain code/text instead of rendering it as math.

This happens with both:

1. $$ ... $$
2. fenced math blocks: ```math ... ```

Why this matters

In CommonMark/GFM list writing, indentation is needed to keep follow-up content in the same logical list item.

• Without indentation, math renders, but the content visually/structurally breaks out of the list item.
• With indentation, structure is preserved, but math rendering is lost.

Repro case (minimal)

* **Shift the input sequence:** Let $x_1[n] = x[n - n_0]$. The output is:

  ```math
  y_1[n] = \sum_{m=-\infty}^{n} x[m - n_0]
  ```

  Perform a change of variable: let $k = m - n_0$.

Actual behavior

The math block is rendered as a plain source-code block (not as KaTeX/display math). The following screenshot image is taken on GitHub.com built-in Preview of the above sample source code.

Expected behavior

Indented math delimiters used as list-item continuation should still be recognized as math and rendered accordingly. The attached screenshot image is taken on VS Code with its built-in Markdown Preview.

Notes

• If the same math delimiters are moved to column 0 (no indentation), math renders correctly.
• But in that case, the block is no longer visually/structurally part of the list item.
• This seems to be an interaction between list continuation parsing and math delimiter recognition.

I’m happy to help test possible fixes with additional examples.

Thanks!

[aimanfazal]

Answer

This looks like a valid GitHub Markdown rendering bug involving math blocks inside continued list items.

The issue is that when a math delimiter is indented to remain part of a list item, GitHub renders it as plain text instead of mathematical notation.

Expected behavior

Indented math blocks should still be recognized and rendered as math while remaining inside the list item.

Current behavior

The same math block renders correctly when moved to column 0, but loses math rendering when indented for list continuation.

Suggested fix

GitHub's Markdown parser should handle list-item continuation indentation before processing math delimiters, so constructs such as $$...$$ and fenced ```math blocks can still be recognized inside list items.

The minimal reproduction and comparison with VS Code in the post should make this straightforward to reproduce.

If this answer was helpful, please mark it as answered.

[kurupdevs]

GitHub only recognises display maths when each $$ sits on its own line with a blank line before and after the block, and inside a list item every line of that construct must be indented to align with the list item's content, for example two spaces beneath a "- " marker. A fenced ```math block needs the same handling: a blank line above the opening fence plus consistent list-item indentation. In your repro the fence sits immediately under "The output is:" with no blank line between them, so the parser treats it as ordinary text rather than maths. Try restructuring the item as text, blank line, indented $$ on its own line, formula, indented $$, blank line, and the block should render while staying inside the list.

[TheVingance]

Hi @MikeProjects,

The root cause in your minimal reproduction comes down to two strict constraints in GitHub's Markdown parser (built on CommonMark + MathJax):

1. Fenced Code Blocks Require Line Breaks: GitHub's math fence parser strictly expects the opening fence, the math content, and the closing fence to sit on separate, dedicated lines. Having the entire expression on a single line causes the engine to bypass the MathJax pipeline and fall back to standard raw code block rendering.
2. List Item Continuation Indentation: For any block element (such as a fenced block or a $$ display math block) to remain logically inside an unordered list item without breaking the tree, every line must carry the exact column indentation of the list item's first character (typically 2 spaces for * or 4 spaces for numbered lists), preceded by an empty line.

---

Working Fixes for Your Exact Example

Option 1: Multi-line fenced math block (Preserves list structure)

Ensure an empty line precedes the fence, and keep each delimiter on its own line indented by 2 spaces:

• Shift the input sequence: Let $x_1[n] = x[n - n_0]$. The output is:

$$y_1[n] = \sum_{m=-\infty}^{n} x[m - n_0]$$

Perform a change of variable: let $k = m - n_0$.

---

Option 2: Using indented $$ display delimiters

If you prefer standard TeX display math over code fences, place both $$ delimiters on their own lines, separated by empty lines, and aligned with 2 spaces:

• Shift the input sequence: Let $x_1[n] = x[n - n_0]$. The output is:
  $$y_1[n] = \sum_{m=-\infty}^{n} x[m - n_0]$$

Perform a change of variable: let $k = m - n_0$.

---

Option 3: Using HTML <li> (Bypasses markdown indentation ambiguity)

If you have nested lists with complex multi-paragraph equations where indentation rules become brittle:

Both Option 1 and Option 2 will render properly as rendered MathJax while keeping the structural hierarchy intact on GitHub.

If this solution resolves the issue in your documentation, please consider marking this as the accepted answer!