I know that I can add spacings in equations using \,, \: and \;. However, by default, there is no spacing between two factors. Do I have to set every spacing manually using the above commands, or is there a way to increase the default spacing?
Thanks!
Edit: In my case, an equation looks something like this:
... but should be more like this:
.
(I guess, alternatively I could just add \cdots between the characters to make it look nice, but the question still stands.)
Note that the math italic font already has large sidebearings so that adjacent letters look like a product of variables not a word. That is why fall is unreadable in the subscript shown and should be \mathrm{fall} or \mathit{fall} so that it uses a font without this feature.
The amount of space between these letters is considered part of the font design so the only way to change it in tex is to add spaces between each letter or to try a different font.
As shown below the spacing differences between math and text italic are mostly subtle but have a distinct effect on comprehension. But some letters, notably f, the spacing differences can be quite dramatic.
\documentclass{article}
\begin{document}
$6\pi r v_{fall} \eta$ painful!
$6\pi r v_{\mathit{fall}} \eta$ math italic main text and subscript
$6\pi r v_{\mathrm{fall}} \eta$ math italic main text roman subscript
$6\pi \mathit{r v_{\mathrm{fall}}} \eta$ text italic main text, roman subscript
\end{document}
v_{\mathit{fall}}orv_{\mathrm{fall}}– Johannes_B Apr 10 '16 at 12:03v_\textnormal{fall}, see here, for example – riddleculous Apr 10 '16 at 12:13mathord, you should be prepared to change the values of\thinmuskip,\medmuskip, and\thickmuskipas well. All in all, don't underestimate the complexity of such a project. – Mico Apr 10 '16 at 13:09