# [NTG-context] Comma spacing in math mode

Sun Feb 27 20:58:41 CET 2011

On Sun, 27 Feb 2011, S Barmeier wrote:

> I don't know if anyone feels the same, but I'm not happy with the
> spacing of commas in math mode (pictures attached). For instance,
> typesetting H^1(X,F), the comma seems to be closer to the F than to the
> X. Equal spacing on both sides or setting the comma closer to the X are
> I guess a matter of taste (inserting a \neghairspace after the X
> achieves the latter). In any case, I would kind of prefer equal spacing.

\setupmathematics[autopunctuation=no]

@Hans: I would suggest that this should be made the default.

> Also, it seems odd that adding a negative space \neghairspace does not
> change the length of the total formula - I had expected the modified one
> to be slightly shorter...?

> On a related issue, the spacing for lists, e.g. (0,0,...,0), is not
> satisfactory. LaTeX provides a command \dotsc for dots between commas
> (and other commands like \dotsm, \dotsi, \dotsb). I don't know if all of
> these are necessary, but \dotsc and its cousins are not defined in
> ConTeXt and both using \ldots or just ... give unsatisfactory results.
> (It is also curious that the spacing after the first comma and the
> spacing after the last comma in (0,0,...,0) is evidently different...)
> Personally, I think I favour something approximating (0, 0, ..., 0) and
> I find \ldots is spaced too widely, ... too closely, and in any case,
> the spacing of the dots doesn't match with the spacing of the commas.
>
> Any second opinions?

Adding the \dots(m|i|b|) etc from amsmath is a good idea. I will look into
that.

> P.S.: I'm also confused about \colon and : - the latter looks better to
> me in $i: A \to B$. The spacing for projective coordinates [1:0: ... :0]
> is wide but still acceptable. The index of a subgroup |G:H| is far too
> widely spaced, but \colon only gives asymmetrical spacing.
> The semicolon seems to undergo the same spacing as the comma, with the
> same problems mentioned above.

I think that the spacing of $i \colon A \to B$ is correct. (Compare from
plain TeX output). I don't know what do you expect from |G:H|. : is
defined as a relation and \colon is defined as a punctuation. Does |G{:}H|
look better? (which forces : to be a math ord).

> P.P.S.: \hairspace does not seem to have any effect in math mode, while
> \neghairspace does. Bug or feature?

Don't know.