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• CommentRowNumber1.
• CommentAuthorJohn Baez
• CommentTimeJul 16th 2010
In the article categorification via groupoid schemes, I removed a distracting query box containing a discussion of how to get a double slash in TeX. The answer was that // works, but is ugly, while prettier things like \sslash may not work for people who don't have the font loaded.
• CommentRowNumber2.
• CommentAuthorTobyBartels
• CommentTimeJul 20th 2010
• (edited Jul 20th 2010)

I put back a little bit of that box, with something approaching mathematical content. If you think that even that bit is useless, then feel free to take it out again. But if David is correct to say ‘One could write $Y \sslash X$ for this nerve’ (which is what I made him say now), then that ought to be in the article somewhere.

• CommentRowNumber3.
• CommentAuthorDavidRoberts
• CommentTimeJul 20th 2010

Edited a bit, incorporating the comment, and Ben’s reply, into the dot points. I deleted the box again.

• CommentRowNumber4.
• CommentAuthorJohn Baez
• CommentTimeJul 20th 2010

Okay, great. Unfortunately I see “One could write Y [little box containing the characters 2, 0, E, B arranged in a square] X for this nerve”, which makes me say to myself, “Yeah, one could write that…”

• CommentRowNumber5.
• CommentAuthorTobyBartels
• CommentTimeJul 20th 2010

Well, that’s why the Lab page also says that you could write $Y//X$ instead, if you can’t see the proper version.

It’s all a question of which fonts you have installed. The character is there, and …

… now that I look at it, it doesn’t look like it is the correct character after all! U+20EB is a combining character, and the correct character is U+2AFD. So this is a bug in iTeX.

Can you see this, John and David? (It is the correct character, put in by hand, so with the wrong spacing.)

$Y⫽X$

• CommentRowNumber6.
• CommentAuthorJohn Baez
• CommentTimeJul 20th 2010

I see a little box with a 2 A F D in it.

• CommentRowNumber7.
• CommentAuthorDavidRoberts
• CommentTimeJul 20th 2010

I see dead people.. :P I mean, I just see a gap. But then, I’m at work, on crusty old Firefox 3.0.1 I was mystified earlier, when I thought Toby was trying to say I could just write YX, but soon realised when I was editing.

• CommentRowNumber8.
• CommentAuthorTobyBartels
• CommentTimeJul 20th 2010

Depending on the computer I use, I see all kinds of things: blank spaces, boxes like John, and double slashes.

• CommentRowNumber9.
• CommentAuthorTobyBartels
• CommentTimeJul 22nd 2010

By the way, Jacques has fixed the iTeX bug that renders \slash as one character that y’all can’t see instead of another, correct character that y’all can’t see, although it hasn’t propagated to us yet.

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• To produce a hyperlink to an nLab entry, simply put double square brackets around its name, e.g. [[category]]. To use (La)TeX mathematics in your post, make sure Markdown+Itex is selected below and put your mathematics between dollar signs as usual. Only a subset of the usual TeX math commands are accepted: see here for a list.

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