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Re: Exploring new vocabularies for HTML

From: Bruce Miller <bruce.miller@nist.gov>
Date: Sat, 29 Mar 2008 22:07:58 -0400
To: Henri Sivonen <hsivonen@iki.fi>
Cc: David Carlisle <davidc@nag.co.uk>, ian@hixie.ch, public-html@w3.org, www-math@w3.org
Message-id: <47EEF5FE.4080403@nist.gov>

[I'm speaking for myself, here; not for the Math WG, nor even NIST]

Henri Sivonen wrote:
> On Mar 30, 2008, at 00:23, David Carlisle wrote:
>> But as I just replied to Ian, annotation-xml for anotation
>> presentation mathml with content is used a lot, and anotation is often
>> used to anotate mathematics with alterative (ofetn original source)
>> forms suct as openofiiceorg syntax, or maple, or TeX...
> 
> I think annotation and annotation-xml are harmful when used as 
> alternative representations of a MathML subtree as opposed to a 
> validator-pleasing escape hatch to SVG.
> 
> Why would anyone include an alternative format for a MathML subtree 
> unless they expected a human or a piece of software to process the 
> alternative format instead of MathML? That leads to a situation where 
> different consumers use different alternatives that might not be equally 
> expressive and in sync.

I think there's some confusion here --- tho' it may be mine.
I personally think the most compelling case for annotations,
especially in a web context, is to provide presentation MathML
for display to humans, along with the corresponding content
MathML (when available) for export to applications (or perhaps
for audio rendering, or ...).  For any non-trivial math, for
software to infer the meaning from the presentation is really
just a wild guess; humans do somewhat better.  Perhaps the
notion of a "semantic web" has lost its popularity, but this
use case seems to be exactly what a semantic, and accessible,
web needs.

I do somewhat share the concerns about using annotations to embed other
applications' internal forms, leading to bypassing the MathML
entirely, and increasing chances of the forms getting out of sync.

But even so, _if_ there is the means for a browser to skip over a
content mathml annotation, that mechanism could as easily skip
other annotations as well --- provided it can find the end of
the annotation, which of course is not necessarily trivial
once you're outside of the XML world.

> After discussing this with Hixie on IRC and testing a bit with Gecko, 
> I'd like revise my position. Since SVG in MathML works fine in the #1 
> SVG-in-MathML browser engine implementation (Gecko in Firefox 3), I 
> think requiring the <semantics><annotation-xml encoding="SVG1.1"> cruft 
> around <svg> is just silly and it would be better to make <svg> subtrees 
> conforming directly inside Presentation MathML.

I'm not sure I'm catching the relevance of SVG here...
I could see an argument for allowing SVG inside presentation
MathML with the sense of "This is just a token that looks _this_ way",
though it would probably be best if it were wrapped in an
mo, mi, mtext, or whatever.
There are some worries about exporting such expressions to
a MathML application.

Further, I would also agree that specifying an annotation as SVG
seems somewhat silly, since it's presumably just providing another
way to present something that is already sufficiently described.

Som, I think SVG is somewhat of a distraction to the topic
of semantics/annotation since it isn't really the main
justification for it.
Of course, it very much _is_ relevant to discussions of mixing
html/mathml/svg at various levels.

-- 
bruce.miller@nist.gov
http://math.nist.gov/~BMiller/
Received on Sunday, 30 March 2008 02:09:15 GMT

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