John Baez [#26](

> Daniel Fava had written:

>> (Couldn't figure out \{ so going with [ instead)

> For some weird reason, on this particular installation of MathJax we need to type

> `\\{`

> to get a {, and similarly for }. Two backslashes before { and }. I don't know why. I fixed the problem for you.

To make this less mysterious to anyone curious, it's caused by multiple layers of text processing. The wiki software gives special meaning to some characters like \*, so if you want the actual character instead of italics, you have to "escape" it by typing \\\*, which means "treat the character after the \\ as raw text".

I'm guessing that MathJax uses the same escape character to identify math commands. That means you have to escape the escape as \\\\, which the wiki reads as an escaped backslash character, emitting a single backslash. So you type \\\\\( and MathJax actually sees the processed text \\\(.

This meta-escaping grows exponentially with the number of processing layers! I've had to use quadruple backslashes to represent a single backslash in some programming situations. (I chose to write this comment without using yellow `literal text`, so there's a sea of backslashes in the source text.)