# Why does this produce math equations indented with grey bar?

By looking at the posts on Mathematics Stack Exchange I have figured out how to produce an inset of math equations, like this:

$$S=\{1,2,3\ldots \text{ n for }n\in \mathbb{N}\}\\ Y_{i,j}=\{i|i\in \mathbb{N}\land j|j\in \mathbb{N}\}$$

The result that you see, a light grey box to the left of inset equations, is begun by putting a > just before the \$ and concluding with an extra return at the end. I have searched the internet the world over and failed to find this feature documented. Can someone please point me to some documentation? If this is a LaTeX feature, I can't find that either.

• It is documented in the help pages. – Xander Henderson Feb 10 at 17:39
• Perhaps the title should ask "How" rather than "Why"? – hardmath Feb 10 at 18:33

## 1 Answer

This isn't part of MathJax or LaTeX; it's part of Markdown, which is the Stack Exchange way of formatting posts in general (e.g. italicizing the name Markdown, or making formatted links).

What you stumbled upon is the blockquote; the linked Help Center article contains almost all other options available to you.