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1. • CommentRowNumber1.
   • CommentAuthorUrs
   • CommentTimeJul 19th 2013
   • (edited Jul 19th 2013)
   • PermaLink
   Author: Urs
   Format: MarkdownItexI find the spacing around colons in math mode on the nLab too small. Whenever I note down a map f \colon X \to Y I feel like I have to replace it by f \;\colon\; X \to Y in order for the output to look nice. Especially if $f$ ad $X$ here are themselves more complicated expressions, then the standard spacing puts them so close together that it takes effort to convince the eye that $X$ belongs more to $Y$ than to $f$, if you know what I mean. Would it be hard to change that spacing a bit? And before that: does anyone agree with this sentiment?

   I find the spacing around colons in math mode on the nLab too small. Whenever I note down a map

   f \colon X \to Y
   

   I feel like I have to replace it by

   f \;\colon\; X \to Y
   

   in order for the output to look nice. Especially if $f$ ad $X$ here are themselves more complicated expressions, then the standard spacing puts them so close together that it takes effort to convince the eye that $X$ belongs more to $Y$ than to $f$, if you know what I mean.

   Would it be hard to change that spacing a bit? And before that: does anyone agree with this sentiment?

2. • CommentRowNumber2.
   • CommentAuthorTodd_Trimble
   • CommentTimeJul 19th 2013
   • PermaLink
   Author: Todd_Trimble
   Format: MarkdownItexI agree with it. To my eye, there's little difference between \colon and : .

   I agree with it. To my eye, there’s little difference between \colon and : .

3. • CommentRowNumber3.
   • CommentAuthorMike Shulman
   • CommentTimeJul 20th 2013
   • PermaLink
   Author: Mike Shulman
   Format: MarkdownItexI use : now for maps anyway, and the spacing doesn't bother me.

   I use : now for maps anyway, and the spacing doesn’t bother me.

4. • CommentRowNumber4.
   • CommentAuthorUrs
   • CommentTimeJul 20th 2013
   • PermaLink
   Author: Urs
   Format: MarkdownItexEr, I thought it was you and Toby who once conviced me to use \colon instead of : in math mode. Apparently I am misremembering.

   Er, I thought it was you and Toby who once conviced me to use

    \colon
   

   instead of

     :
   

   in math mode. Apparently I am misremembering.

5. • CommentRowNumber5.
   • CommentAuthorMike Shulman
   • CommentTimeJul 20th 2013
   • PermaLink
   Author: Mike Shulman
   Format: MarkdownItexNo, that's correct. I've just [changed my mind since then](http://nforum.mathforge.org/discussion/2311/linear-logic/?Focus=31862#Comment_31862).

   No, that’s correct. I’ve just changed my mind since then.

6. • CommentRowNumber6.
   • CommentAuthorTodd_Trimble
   • CommentTimeJul 20th 2013
   • PermaLink
   Author: Todd_Trimble
   Format: MarkdownItexThe only difference I can detect between $x : A$ and $x \colon A$ is that, to my eye, there seems to be ever slightly more space between the $x$ and the colon in the second one (which seems to run counter to what people were saying in the other thread Mike just linked to). Are other people seeing more space between $x$ and the colon in the first case?

   The only difference I can detect between $x : A$ and $x \colon A$ is that, to my eye, there seems to be ever slightly more space between the $x$ and the colon in the second one (which seems to run counter to what people were saying in the other thread Mike just linked to). Are other people seeing more space between $x$ and the colon in the first case?

7. • CommentRowNumber7.
   • CommentAuthorUrs
   • CommentTimeJul 20th 2013
   • (edited Jul 20th 2013)
   • PermaLink
   Author: Urs
   Format: MarkdownItexI just checked in [[Sandbox]] and come to the same conclusion as Todd: the actual difference between \colon and : is that the second produces even _less_ spacing in front. Which indeed seems to run counter both to that discussion and to the general idea that the first should be punctuation and the second relation. All the more I have my original question: > Is it hard for us (hence for Andrew) to _change_ the spacing? It needs to be wider, in either case.

   I just checked in Sandbox and come to the same conclusion as Todd: the actual difference between

    \colon
   

   and

    :
   

   is that the second produces even less spacing in front. Which indeed seems to run counter both to that discussion and to the general idea that the first should be punctuation and the second relation.

   All the more I have my original question:

   Is it hard for us (hence for Andrew) to change the spacing?

   It needs to be wider, in either case.

8. • CommentRowNumber8.
   • CommentAuthorTobyBartels
   • CommentTimeJul 21st 2013
   • PermaLink
   Author: TobyBartels
   Format: MarkdownItexIt seems to me that iTeX is rendering both `\colon` and `:` incorrectly into MathML. While `\colon` becomes `<mo lspace='verythinmathspace'>:</mo>` (which is equivalent to `<mo lspace='verythinmathspace' rspace='verythinmathspace'>:</mo>` using the defaults at <http://www.w3.org/TR/MathML3/appendixc.html>), it really should be `<mo lspace='nomathspace' rspace='thinmathspace'>:</mo>` (which is analogous to the defaults of, say, `,`). Even worse, while `:` becomes simply `<mo>:</mo>` (equivalent to `<mo lspace='veryverythinmathspace' rspace='verythinmathspace'>:</mo>` using the defaults), it really should be `<mo lspace='thickmathspace' rspace='thickmathspace'>:</mo>` (which is analogous to the defaults of, say, `=`). The difference with `\colon` is not very big, but the difference with `:` is significant. This should be considered a bug in iTeX.

   It seems to me that iTeX is rendering both \colon and : incorrectly into MathML. While \colon becomes <mo lspace='verythinmathspace'>:</mo> (which is equivalent to <mo lspace='verythinmathspace' rspace='verythinmathspace'>:</mo> using the defaults at http://www.w3.org/TR/MathML3/appendixc.html), it really should be <mo lspace='nomathspace' rspace='thinmathspace'>:</mo> (which is analogous to the defaults of, say, ,). Even worse, while : becomes simply <mo>:</mo> (equivalent to <mo lspace='veryverythinmathspace' rspace='verythinmathspace'>:</mo> using the defaults), it really should be <mo lspace='thickmathspace' rspace='thickmathspace'>:</mo> (which is analogous to the defaults of, say, =). The difference with \colon is not very big, but the difference with : is significant. This should be considered a bug in iTeX.