I use LyX 2.3.1 under Windows 10.
I'm trying to create an "operator" for the infinitesimal d. Thus, instead of
writing $dx$ -- which leads to "d" in italic font, I go to Document/Settings...
and the LaTeX Preamble field:
\DeclareMathOperator{\diff}{d}
Next, in the document, I write $\diff x$, i.e., I type: \diff + space + x when
in math mode. The result is that "d" is typeset in roman font, which is what I
want.
HOWEVER, the spacing between the roman d and the x is a little bit too large to
be pretty.
OK -- I have tried to insert a negative space (\! + space) in the document, and
that helps. However, now the spacing is a little bit too small...
* Question: is there a slightly smaller negative spacing?
Also: how can I insert the negative space into the operator definition? Doing:
\DeclareMathOperator{\diff}{\! d}
doesn't work.
Thanks!
-B
