• To: math-font-discuss@cogs.susx.ac.uk
• Subject: Question about Euler arrows
• From: Ulrik Vieth <vieth@thphy.uni-duesseldorf.de>
• Date: Mon, 29 Sep 1997 12:29:48 +0200


This weekend, I've been re-reading Knuth's article on Typesetting
Concrete'' from TUGboat 10#1.

I noticed that the explanation given for the design of the Euler
arrows in euex10 was to make the arrowheads darker in order to match
the color of the Euler fonts.  If you look at the code in ebigob.mf,
you'll find that this was realized by setting |bar:=rule_thickness;|
and copying the code for the arrows from the CM font programs in
symbol.mf (as of 1988 or some such).  Meanwhile, in 1992, Knuth
has redesigned the CM arrows, making the arrowheads not only darker
(by a smilar change as above), but also bigger by a change of the
font programs.

Now, I was wondering, if there is still any justification to have
different Euler arrows at all, or whether the post-1992 CM arrows
would do just as well?  That is, should the Euler version of MSP
really take the arrows from euex10 or better use CM arrows instead?
Note that in both cases, the extension pieces \relbar and \Relbar
must come from CM anyway (-' from cmsy, =' from cmr (or ccr?)),
since the Euler -' and =' won't fit without bumps.

Opinions anyone?

Cheers, Ulrik.

P.S. Another comment about Euler: It appears that the \prime should
still come from cmsy (matching the \backprime from msam).  The single
quote from eufm10, which apparently was taken in my previous tests,
seems to be usable only for text.