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RE: What is "f'(x)" as MathML?

From: J.Fine <j.fine@open.ac.uk>
Date: Fri, 21 Jan 2011 16:47:48 +0000
To: 'Robert Miner' <robertm@dessci.com>, Daniel Marquès Solé <dani@wiris.com>, J.Fine <j.fine@open.ac.uk>, "www-math@w3.org" <www-math@w3.org>
Message-ID: <A969C9F865F27B428A8E60E39D3CED154AC1D83ED5@KIELDERCMS1.open.ac.uk>
Hello Robert

Thank you so much for this clear explanation of one of the causes of this problem.  You've inspired me to find the page

"Unicode has subscripted and superscripted versions of a number of characters including a full set of arabic numerals. These characters allow any polynomial, chemical and certain other equations to be represented in plain text without using any form of markup like HTML or TeX."

It further goes on to quote say
The World Wide Web Consortium and the Unicode Consortium have made recommendations on the choice between using markup and using superscript and subscript characters: "When used in mathematical context (MathML) it is recommended to consistently use style markup for superscripts and subscripts...However, when super and sub-scripts are to reflect semantic distinctions, it is easier to work with these meanings encoded in text rather than markup, for example, in phonetic or phonemic transcription." [http://www.w3.org/TR/unicode-xml/#Superscripts]

It is, for us, unfortunate that there is no SUPERSCRIPT PRIME (similar to SUPERSCRIPT ZERO etc).  As a result, glyph implementors have provided SUPERSCRIPT PRIME at the code point PRIME while MathML implementors have assume that PRIME is at PRIME.  See

According to http://www.cl.cam.ac.uk/~mgk25/ucs/examples/TeX.txt (Markus Kuhn), "(Unicode 3.2 lacks a dot-less j and a non-superscript prime)".

The best solution I can think of for this mess is EITHER to introduce a NON-SUPERSCRIPT PRIME code point or a SUPERSCRIPT PRIME code point.  Either way, something has to be changed to get everything to work.  (I think we knew that already.)  My preference is to accept that the standard made a mistake but can't be changed and so introduce NON-SUPERSCRIPT PRIME (and insist that the Unicode documentation recognize that a mistake was made).

With best regards


> -----Original Message-----
> From: Robert Miner [mailto:robertm@dessci.com]
> Sent: 21 January 2011 15:50
> To: Daniel Marquès Solé; J.Fine; www-math@w3.org
> Subject: RE: What is "f'(x)" as MathML?
> A problem that comes up with the <mi>f</mi><mo>'</mo><mo>
> style of markup is that it doesn't accommodate stacked
> scripts well.  That is, notations like
> <msubsup>
>   <mi>f</mi>
>   <mn>0</mn>
>   <mo>&prime;</mo>
> </msubsup>
> This is a problem for the whole class of characters that
> notationally function as superscripts, but that Unicode
> considered to merely be instances of characters that happen
> to be "pre-shrunk" and raised above the baseline.  MathML 3
> terms these characters pseudoscripts, and there are around 20
> or so, including various primes and backticks, the degree
> symbol, asterisk and some others.
> I assume that Unicode was forced into considering things like
> degree and asterisk as pre-shrunk, raised characters by
> backward compatibility considerations long ago, and merely
> carried forward that decision consistently.  But given the
> importance of the stacked script case in practice, it wasn't
> a very good decision.  To accommodate that case, renders have
> to special case those characters in some fashion.
> Anyway, I just wanted to mention this, since apart from other
> more theoretical, semantic considerations, in working with
> STEM publishers using MathML is big work flows, the practical
> stacked script has been the dominant consideration.
> --Robert
> > -----Original Message-----
> > From: www-math-request@w3.org [mailto:www-math-request@w3.org] On
> > Behalf Of Daniel Marquès Solé
> > Sent: Thursday, January 20, 2011 9:00 AM
> > To: J.Fine; 'www-math@w3.org'
> > Subject: RE: What is "f'(x)" as MathML?
> >
> > Hello,
> >
> > I my modest opinion
> > <math><mi>f</mi><mo>'</mo><mo>(</mo><mi>x</mi><mo>)</mo></math>
> >
> > Regards,
> >
> > Dani
> >
> > -----Original Message-----
> > From: www-math-request@w3.org [mailto:www-math-request@w3.org] On
> > Behalf Of J.Fine
> > Sent: jueves, 20 de enero de 2011 15:37
> > To: 'www-math@w3.org'
> > Subject: What is "f'(x)" as MathML?
> >
> > Hi
> >
> > Forgive me for asking a question that might already have been
> > answered, but what is the 'correct' translation of the TeX notation
> > mathematics "f'(x)" into presentation MathML?
> >
> > With best regards
> >
> >
> > Jonathan
> >
> > --
> > The Open University is incorporated by Royal Charter (RC
> 000391), an
> > exempt charity in England & Wales and a charity registered
> in Scotland
> > (SC 038302).
> >
> >
Received on Friday, 21 January 2011 16:49:23 UTC

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