## LtU now supports Mathjax

LtU now supports MathJax, which allows the use of TeX markup in posts and comments. Note that only TeX/LaTeX markup is currently supported - the alternate MathML format conflict's with the blog's HTML sanitization.

This enhancement is dedicated to neelk, who most recently suggested this feature just over a year ago.

When I went searching for a bit of Mathjax-compatible LaTeX that was relevant to programming languages, the first good example Google found for me was on Neel's blog:


Copy-pasting the above and making it work immediately made it clear that we're going to need a package of useful macros. But it's a start. Feedback welcome.

Note that MathJax rendering is entirely client-side - if you don't see a well-formatted formula above, check the MathJax browser compatibility page and their FAQ.

## Comment viewing options

### As if we weren't too

As if we weren't too highbrow already... Thanks, Anton!!

### That reminds me

That reminds me, from now on all comments(after this one) must include a correctness proof, which will be mechanically checked by Drupal's PHP proof-checking module before it is published.

### This sentence is false.

This sentence is false. :)

### Congrats John

I think it's everyone here's dream to have their research find its way into an esoteric language.

### Cool beans

$$f \sqsubset \lambda x. x \bot$$

(And thank you, Anton)

### Nice but not strictly necessary

$$f \sqsubset Ï x. x \bot$$

I cut and pasted a proper Unicode vau there instead of \lambda, and all is well, except that the font makes it look too F-ish for my taste. (Ï is the ancestor of F, as we learn from "For Ant Of A Nail", a fanfic starring Xenwa, Warrior Wprincess.)

### Except I didn't use that

Except I didn't use that form of the letter. Conlangers may appreciate — the modern forms of the letter seemed over-similar to F, leading to possible confusion, so I chose a different ancient form of the letter that didn't survive (a left-right reflection of F), and supposed that it had undergone transformations over time analogous mutatis mutandis to what happened to the letter F.

### The symbol that looks like

The symbol that looks like our F is (according to my hardcopy Britannica from the 1970s) the Chalcidian form of vau. I based my alternative history on the Corinthian, but I don't see that in the Wikipedia article about digamma. However, if you look at the Wikipedia artice F, the version of digamma shown there atm is the one I started from. (I ended up with something that looks pretty much like $$f$$, except the curve at the top goes left and the curve at the bottom goes right.)

(Aside: We're told "digamma" is called that because it looks like two gammas of different sizes written on top of each other. But as that nifty fanfic linked above notes, the ancient greeks used letters to represent numbers: alpha=1, beta=2, gamma=3, delta=4, epsilon=5, vau=6, until things got more complicated after ten. So the numerical value of vau is twice that of gamma. I've wondered about that.)

### Latin small letter l with bar?

You could possibly use U+019A as a substitute. In some fonts (Gentium, for example), the 'l' is quite similar to a reversed Digamma.

edit: It actually works well in the Monospace of the comment entry box on this site, although in the Arial of the actual posts, the l is just a straight line. (Striking through an l in tex would work, but I can't find any way to do it in Mathjax.)

### Hunting through unicode,

Hunting through unicode, closest I've come is U+285 followed by U+335, italicized, but the horizontal bar doesn't comes out quite right.

Text: Ê…Ìµ

Mathjax: $$\it Ê…Ìµ$$

[edit: somewhat better Mathjax: $$\large\it Ê…\hspace{0.2em} Ìµ$$ ]

### This is a good thing

We need more people here who will show how to solve problems in language theory with two or three arrows.