How should I align capital letter subscripts?

Question

I observe that when a word starts with capital letter or non-capital letter as a subscript, then the capital letter looks like it shifted right, as an eye illusion. But when I look closely a and A actually started at exact location.

example:

\documentclass[10pt,journal,compsoc]{IEEEtran}
\usepackage{amsmath}
\begin{document}
\phantom{} \\
    \(C_{a}^{\mathit{pull}}\) \\
    \(C_{A}^{\mathit{pull}}\) \\
    \(C_{d}^{\mathit{pull}}\) \\
    \(C_{D}^{\mathit{pull}}\) \\
\end{document}

Here A looks like it starts kind of 1 space inside. If I use a capitalize word should I shift it left using: $C_{!\A}$ or is there more proper way to do it?

It seems like this is more unique to A than to capital letters in general, since A is the only one with stuff in its bottom left corner but not its top left corner. But I think the question still remains for A. — Teepeemm, Sep 19 '22 at 20:00
The leftmost part of A and D are aligned with the p of pull. Probably the same with E, F etc. — Peter Wilson, Sep 21 '22 at 18:16
@PeterWilson that's right but A and D looks like they shifted 1 space to right compared to a or d — alper, Sep 22 '22 at 10:36
The nature of the glyph. You can see that the glyph starts at the same position: $C_{D}^{\mathit{pull}}$\llap{$C_{d}^{\mathit{pull}}$}. D contains the serif at the bottom. — Sigur, Sep 22 '22 at 13:44
Adjustment would improve the appearance, certainly, but it can't be done automatically, since TeX is aware only of the width of a glyph. Consider "W" and "Y", which have their greatest width at the top, along with an indentation at the baseline. — barbara beeton, Sep 22 '22 at 15:04
As far as LaTeX typesetting is concerned a character is a rectangular box with some graphic inside it. It only deals with the boxes, not their content. See @barbarabeeton's comment. — Peter Wilson, Sep 23 '22 at 18:19

score 1 · Answer 1 · answered Sep 28 '22 at 02:09

1

Disclaimer: I am the author of the package and of the linked solution.

You can take a look at my LaTeX package to handle super and under script based on the actuarial symbol. It can handle by default most super, under script with package function also.

See here my response here.

answered Sep 28 '22 at 02:09

David Beauchemin

515

I was looking for much simple solution where $C_{\!D}}$ would be enough? – alper Sep 28 '22 at 09:14
Yes, but I think interfacing with a command is much simpler IMO. – David Beauchemin Sep 28 '22 at 15:31

score 1 · Accepted Answer · answered Sep 28 '22 at 10:29

The more I look at the picture, the less I feel a need for “fixing”. Anyway, here's the experiment: I define a \fixA command that emits a negative kern. In the four columns, the kerns are zero, -1mu, -2mu and -3mu respectively, the last being the same as \!.

\documentclass{article}
\usepackage{amsmath}
\newcommand{\fixA}[1][1]{\mkern-#1mu}
\begin{document}
\spaceskip=1em
(C_{a}^{\mathrm{pull}}) (C_{a}^{\mathrm{pull}}) (C_{a}^{\mathrm{pull}}) (C_{a}^{\mathrm{pull}})
(C_{A}^{\mathrm{pull}}) (C_{\fixA A}^{\mathrm{pull}}) (C_{\fixA[2] A}^{\mathrm{pull}}) (C_{\fixA[3] A}^{\mathrm{pull}})
(C_{d}^{\mathrm{pull}}) (C_{d}^{\mathrm{pull}}) (C_{d}^{\mathrm{pull}}) (C_{d}^{\mathrm{pull}})
(C_{D}^{\mathrm{pull}}) (C_{D}^{\mathrm{pull}}) (C_{D}^{\mathrm{pull}}) (C_{D}^{\mathrm{pull}})
\end{document}

If you use IEEEtran, I recommend using newtx in order to get Times font also in math (the standard Computer Modern is really unsuited to go with Times). Now you can compare and see that using something like \fixA is better than hardwiring \!.

\documentclass{article}
\usepackage{amsmath}
\usepackage{newtx}
\newcommand{\fixA}[1][1]{\mkern-#1mu}
\begin{document}
\spaceskip=1em
(C_{a}^{\mathrm{pull}}) (C_{a}^{\mathrm{pull}}) (C_{a}^{\mathrm{pull}}) (C_{a}^{\mathrm{pull}})
(C_{A}^{\mathrm{pull}}) (C_{\fixA A}^{\mathrm{pull}}) (C_{\fixA[2] A}^{\mathrm{pull}}) (C_{\fixA[3] A}^{\mathrm{pull}})
(C_{d}^{\mathrm{pull}}) (C_{d}^{\mathrm{pull}}) (C_{d}^{\mathrm{pull}}) (C_{d}^{\mathrm{pull}})
(C_{D}^{\mathrm{pull}}) (C_{D}^{\mathrm{pull}}) (C_{D}^{\mathrm{pull}}) (C_{D}^{\mathrm{pull}})
\end{document}

Instead \usepackage{newtx} can I only use \usepackage{newtxmath}? I observe that section titles also effected when I use newtxtext and fonts in listings; I believe journals wouldn't what their template section fons to be affected — alper, Sep 28 '22 at 10:50
Or can we apply \usepackage{newtx} only for the math-mode? like the text in between $...$ ? and not not effect the text in between \section{ ... } — alper, Sep 28 '22 at 10:55
@alper You might by doing \usepackage{newtxmath}, but the class uses ptm for text, which points to a very old font, whereas newtx is richer. — egreg, Sep 28 '22 at 12:12

How should I align capital letter subscripts?

2 Answers2

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