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.

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?

Best wishes,
Severin

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.

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