[Tex/LaTex] Should Greek letters inserted in text (using math mode, mostly) always be italic

formattinggreekitalic

The least painful way I know of inserting a Greek letter in a text is to use the math mode and the corresponding command. This will produce an alpha letter :

$\alpha$

But this always produces an italic letter. I never thought about it until now, but when should this letter be italic, and when should it not?

Furthermore, if I am talking about microseconds in my text, there will be one Latin and one Greek letter side by side. Which of the following should I use?

1- The average time of this event is 50 $\mu s$.
2- The average time of this event is 50 $\mu$s.
3- The average time of this event is 50 $\mathrm{\mu s}.
4- The average time of this event is 50 μs.

Now to me it's either #1 or #3, as #2 produces one italic letter and one normal letter (that's kind of a visual clash), and #4 is only usable if your document is encoded using UTF-X. What do you do when facing this?

Best Answer

For the case of units, you should use the siunitx package.

\documentclass{article}
\usepackage{siunitx}
\begin{document}
The average time of this event is \SI{50}{\micro\second}.
\end{document}

I guess I should mention the upgreek package.

The average time of this event is 50~$\upmu$s.

but this doesn't look as good.

alt text

Related Solutions

[Tex/LaTex] Bad spacing of math letters within italic text

OK, I produced an absolutely crazy "solution" myself. This is mostly to make clearer what the problems are; I wouldn't suggest using the (very long) code below. This "solution" only provides italic correction for single letters A to Z and a to z, and it works by making $ active. (I could also have used $ and $, but I don't like those.) Moreover, everything is adjusted "by hand" for 10pt CM fonts, so it won't work for other fonts (but should approximately work for other font sizes). Here's the output:

In the 1st line you see the result of If $U$ or $V$ ... without any correction; in the 2nd line my correction is applied, and in the 3rd line the $s are omitted, i.e., the usual italic font is used. I'm not claiming that the 2nd line is good on all counts, e.g. the space between "f" and "from" is rather small. What I wanted to achieve is that the spacing is just as with the "normal" italic font, that is, in the second and third lines the spacing is (almost) the same. (The 2nd line is slightly longer since the math letters are wider.)

Note in particular that the spacing before punctuation in the 2nd line is different from the 1st line. (I'm not sure which version is the better one.) Clearly, the positioning of "U", "V" and "Y" in the 1st line is not good (I would say horrible); in the 2nd line it's a lot better.

Of course one could change all these numbers in my code to try and further improve the spacing. But I only wanted to point out something else: If you look at the numbers, then you see that it would be very hard indeed to have this correction "automatically" and without changing the font metrics.

\documentclass{article}

\makeatletter
\let\mydollar=$
\catcode`\$=\active
\def\my@testtoken{\my@testtoken}
\def$#1${\ifx\my@testtoken#1\my@testtoken
           \mydollar\mydollar
         \else
           \test@single@character#1\my@testtoken
         \fi
        }
\def\test@single@character#1#2\my@testtoken{%
         \def\math@format##1{\mydollar##1\mydollar}%
         \ifx\mytesttoken#2\mytesttoken
           \ifcat#1a%
             \ifdim\fontdimen\@ne\font>\z@
               \def\math@format##1{\mydollar\xdef\currentfont{\the\textfont1}\mydollar
                                   {\corrected{##1}}%\currentfont##1}%
                                  }%
             \fi
           \fi
         \fi
         \math@format{#1#2}%
        }
\def\corrected#1{\csname @correct@#1\endcsname}
\def\correct#1#2,#3,{\expandafter\def\csname @correct@#1\endcsname{\mydollar\mskip#2mu#1\mskip-#3mu\mydollar}}
\makeatother

\correct A0.15,0,    %1st number is the correction before the letter,
\correct B0.3,1.5,   %2nd number is (minus) the correction after it.
\correct C1.75,2.2,
\correct D0.25,1.4,
\correct E0.3,1.7,
\correct F0.3,1.95,
\correct G1.8,1.15,
\correct H0.25,2.6,
\correct I0.3,2.6,
\correct J0.1,2.2,
\correct K0.3,2.4,
\correct L0.25,0.6,
\correct M0.3,2.6,
\correct N0.3,2.6,
\correct O1.75,1.3,
\correct P0.2,1.5,
\correct Q1.75,1.3,
\correct R0.2,0.2,
\correct S0.4,1.8,
\correct T2.7,1.9,
\correct U2.4,2.6,
\correct V2.4,2.95,
\correct W2.4,2.9,
\correct X0.4,2.5,
\correct Y2.6,3.1,
\correct Z0.4,2.2,
\correct a1.2,1,
\correct b1.2,0.3,
\correct c1.2,0.2,
\correct d1.2,0.8,
\correct e1.2,0.85,
\correct f-1.5,3.5,
\correct g0.7,1.2,
\correct h0.4,1,
\correct i1,1.4,
\correct j-0.5,2.2,
\correct k0.4,1.5,
\correct l0.9,1.8,
\correct m1,0.95,
\correct n1,0.95,
\correct o1.2,0.3,
\correct p1,0.3,
\correct q1.2,1.2,
\correct r1,2,
\correct s0.5,1,
\correct t1,1.25,
\correct u1,0.95,
\correct v1,1.55,
\correct w1,1.5,
\correct x0.4,1.75,
\correct y1,1.2,
\correct z0.4,1.75,

\newcommand\test[1]{%
    {\let$\mydollar #1} \par
    #1 \par
    \let$\relax #1
    }

\begin{document}
\it
\test{If $U$ or $V$ and $X$, and $f$ from $j$.  Let $T$ be $S$ if $Y$.}
\end{document}

--- edit ---

Here's a version of the above correction table for use with newtxtext and newtxmath.

\correct A-1.3,-0.2,
\correct B-0.6,0.3,
\correct C0.2,0.9,
\correct D-0.6,0.4,
\correct E-0.55,1.4,
\correct F-2.6,1.1,
\correct G0.0,0.5,
\correct H-0.4,1.0,
\correct I-0.75,1.3,
\correct J-1.0,1.15,
\correct K-0.25,1.3,
\correct L-0.9,0.95,
\correct M-1.0,1.35,
\correct N-2.55,1.55,
\correct O0.25,0.5,
\correct P-0.65,0.45,
\correct Q0.2,0.5,
\correct R-0.8,0.2,
\correct S-0.4,0.6,
\correct T0.7,1.85,
\correct U0.5,1.05,
\correct V0.5,1.65,
\correct W0.5,1.5,
\correct X-1.0,1.45,
\correct Y1.0,1.95,
\correct Z-1.0,1.45,
\correct a-0.3,0.25,
\correct b-0.5,-0.3,
\correct c-0.3,0.35,
\correct d-0.5,0.9,
\correct e-0.25,0.35,
\correct f-3.15,3.15,
\correct g-0.05,0.55,
\correct h-0.6,0.35,
\correct i0.35,0.7,
\correct j-2.0,1.3,
\correct k-0.65,1.3,
\correct l-0.1,1.1,
\correct m-0.2,0.15,
\correct n-0.2,0.0,
\correct o-0.25,0.05,
\correct p-0.75,0.0,
\correct q-0.2,0.4,
\correct r0.2,1.3,
\correct s-0.55,0.45,
\correct t0.15,1.2,
\correct u0.1,0.25,
\correct v-0.1,0.75,
\correct w-0.25,0.6,
\correct x-0.95,0.85,
\correct y-1.0,0.7,
\correct z-0.5,0.55,

[Tex/LaTex] Should subscripts in math mode be upright

Using "all italics" is unfortunately an often committed sin. You should italicize only variables.

Everything else should be upright. For example:

function names (sin, cos, log, ln etc...)
dimensionless numbers (Re, Pr, Ra...)
exact infinitesimal increments (dx, dy et... in BOTH integrals and differentials)
descriptive text
all descriptive variable indices (unless they are also variables)

Exceptions to this rule may still apply, i.e. the Euler-number $e$ is no variable, but still traditionally written in italics.

Some of the above was stolen from the "Please Make A Note" blog. More detailed information can be found in "Typefaces" from NIST.

Best Answer

Related Solutions

[Tex/LaTex] Bad spacing of math letters within italic text

[Tex/LaTex] Should subscripts in math mode be upright

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