# Re: proposal by Bruce Smith

• To: w3c-math-erb@w3.org
• Subject: Re: proposal by Bruce Smith
• From: Nico Poppelier <nico@valacar.elsevier.nl>
• Date: Tue, 4 Jun 1996 09:26:07 +0200 (MET DST)
• From nico@valacar.elsevier.nl Tue Jun 4 03: 21:55 1996
• Message-Id: <199606040726.JAA02110@thorin.elsevier.nl>
• X-Mailer: ELM [version 2.4 PL25]

Here are my comments and questions on the proposal recently distributed
by Wolfram Research.

1. What are the sources of inspiration for this proposal? Or,
to be more direct: is this similar or identical to Mathematica?

2. Concerning special characters: I think it is more accurate to
write "most of which are not part of Unicode" instead of
"not all of which are part of Unicode". I have been in touch
with Anders Berglund, the editor of ISO Technical Report 9573
special characters. We are trying to harmonize the Elsevier
Science set with the set in ISO TR 9573. Anders has also been in
touch with the Unicode people, but they have never answered to
his proposal to add all special characters in ISO TR 9573 to Unicode.

3. Stretchiness of brackets is not 100% static. I mean: I some cases
the user/author should be allowed to differentiate between
( ... ) and \left( ... \right) as in TeX. In the first case the
brackets are not stretchy and in the second case they are.

4. A similar remark for rendering of limits on a sum or integral:
what is described in the proposal is the default, but the author
should be able to override the default.

5. Another remark about large operators: I did not find an explanation
of how to obtain sum' from k=0 to infinity or sum* frm k=0
to infinity, i.e. with a summation that has an ornament in the
normal superscript position. (I know how to do it in TeX, but
I'll spare you that :-).

6. I think a necessary ingredient of (5) is the reverse of "mlargeop":
make a regular operator out of a large operator.

7. I found the explanation of % ^ _ terse (almost cryptic).
Same for the concept "aligned pair", and the application to
tensor notation (with which I should be familiar, since I am
a theoretical physicist. :-).

8. The case where an entire pair of vertically aligned indices
is empty is indeed rare, but we have found examples of it.
So what is the solution to this (or workaround)?

9. What is the equivalent of a^{b^{c}} in TeX (with c in smaller
font than b, which is in smaller font that a)? Surely
not the mbox construction?

10. I am looking forward to treatment of the additional topics
arrays, commutative diagrams, multi-line equations with horizontal
alignment, and equation numbering (I was promised
an explanation of Mathematica's mechanism for this a couple of
months ago, but never got it :-( ).

Sorry I didn't join the conference, but I only finished reading the
proposal this morning.

Regards,

Nico

------------------------------------------------------------------------
Dr. Nico A.F.M. Poppelier
Elsevier Science, APD, ITD               Email: n.poppelier@elsevier.nl.
Molenwerf 1, 1014 AG Amsterdam           Phone: +31-20-4853482.
The Netherlands                          Fax:   +31-20-4853706.
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The truth, the whole truth, and nothing but the truth.
And maybe some compromises.