# Re: Binary Relations, draft 1

• To: Hans Aberg <haberg@matematik.su.se>
• Subject: Re: Binary Relations, draft 1
• From: Thierry Bouche <Thierry.Bouche@ujf-grenoble.fr>
• Date: Tue, 17 Nov 1998 18:44:10 +0100 (MET)
• Cc: math-font-discuss@cogs.susx.ac.uk
• Content-Length: 1511

» The first rule about typesetting rules of pure math I think is that there
» is none such rule! :-)

The big problem being that TeX does follow rules.

» However, the rule is certainly known in the US -- it says something about
» that functions and variable should be typeset this or another way (or have
» forgotten the exact wording), and it is always used.

as for italicising variables yes, this is definitely a general
rule. As for upright constants, it is much less dominant (but, tell
me, why are _digits_ upright in TeX, if not because they're denoting
constants!)

Imho, the case of greek letters is different, but requires much
attention _because_ we may now do this right. I think i already said
here what i think: French tradition has used for years didot's greek,
french printers usually had that one. Simultaneously, english printers
had Porson's greek (much more cursive than didot's, and inclined, very
similar du cmmi, indeed). Hence the constant \pi was typeset upright
on the good side of the channel, inclined on the other one (they also
drive on the wrong side of the streets!).

Well, now the technology allows us to devise a much more coherent &
powerfull system, distinguishing between  the function $e$ and the
Euler constant $\E$, between the projector $\pi$ and the constant
$\PI$, &c.

Compare $e_x(f) = f(x)$ and $f(x) := e^x$ (in the second case, even
$f$ should be upright, no?) :-)

Thierry Bouche, Grenoble.