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Re: [MathML3-last-call] mathvariant

From: William F Hammond <hammond@csc.albany.edu>
Date: Tue, 13 Oct 2009 17:38:16 -0400
To: www-math@w3.org
Message-ID: <i7hbu3km9j.fsf@hilbert.math.albany.edu>
Sorry, I've not really been following this, but several things
in this thread today have grabbed me.

Karl Tomlinson <w3@karlt.net> writes:

> . . .
>> Note that the appearance
>> of a mathematical alphanumeric symbol character should not be altered
>> by surrounding <att>mathvariant</att> or other style declarations.</p>

Is the meaning here of 'other style declarations' limited to MathML
markup or does it extend to CSS?  I think it should not extend to CSS.

> . . .
>> Renderers may ignore or support those combinations of character data
>> and <att>mathvariant</att> values that do not correspond to an assigned
>> Unicode code point,
>
> ... and this sentence says "may", implying that the better
> behavior for renderers is to alter the appearance of all
> non-mathematical-alphanumeric-symbol characters according to the
> mathvariant attribute when possible.

In view of the 2nd paragraph below I'm confused.  Is it thought
correct to use 'mathvariant' for switching on, for example, italic
style?

> This would be a change from MathML2, so I just want to check that
> this has been thought through.
>
> This would effectively mean that almost all
> non-mathematical-alphanumeric-symbol characters in an mi element
> without an explicit mathvariant attribute should be rendered in an
> italic form.

(Is it clear what portion of 'mathematical-alphanumeric' is negated
by the 'non'?)

As I have understood things, a string matching the pattern /^[A-Za-z]$/
(i.e., a single alphabetic character) inside an mi should by default be
rendered italic, but a string matching the pattern /^[A-Za-z][0-9A-Za-z]+$/
should by default be rendered upright.  This is a long-standing tradition
in mathematical typesetting.  I hope you're not suggesting this would change.

> One example to consider is U+221E INFINITY.  ...

With other strings inside an mi my own inclination would be to
be explicit about style -- and I mean style, not character casting --
if I care which way it is set.  Again I ask if the MathML attribute
'mathvariant' is the correct thing to use for that.  CSS is for style.
Isn't mathvariant provided for character casting, i.e., pointing to a
character other than that inside the mi?

> . . .
> One thing that concerns me is that, although we now have better
> Unicode support for mathematical characters than ever, there seems
> to be an increased expectation of creating characters by other
> means that resemble style.

While I do see (and understand) avoidance of the more esoteric reaches
of unicode, e.g., plane 1, I think the tools of avoidance should not
be style.  As I've said, I don't see mathvariant as stylistic.

                                    -- Bill
Received on Tuesday, 13 October 2009 21:38:51 GMT

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