Re: MathML-Presentation questions

Dear Genevieve,


> The company I work for uses MathML (and XML) for encoding educational 
> contents. We also have the goal of translating our XML contents in many 
> differents cultural domains. We have encountered some problems that we 
> don't know how to resolve in MathML.

Boy, you came up with a tough list.  Let me try to give some answers,
though in many cases, I'm not sure there are any good answers.

> 1. How do you propose to markup the association of units to quantities?
>   (Ex.: $5, 100 miles/h, 37.5 ºC)
> 	i. Which markup is appropriate?
> 	ii. How do you specify the spacing before or after the quantity?
> 	iii.How do you manage $5 which is translated 5$ in french-canadian, 
> for example?

A similar question was asked privately a while ago.  I am posting a
digest of the answers to the list separately, so it will show up in
the subject line.

> 2. mn. How do you propose to markup periodic numbers?

There is no special way to do this in MathML.  All I can think of
really is to mark it up to look right.  For example:

<mn>2.33</mn><mover><mn>3</mn><mo>&OverLine;</mo></mover>

> 3. mn. How do you propose to markup the ellipsis expressing the infinite 
> non-repeating decimals of a number?
> (Ex.: 3.14159...)
> Is it a postfix operator? We are looking for a form that does not 
> transgress the "number" meaning.

The idea of a postfix operator is interesting.  That would probably
work, though you might have to tweak the spacing.  However, I think a
more straightforward approach is just to include it in the MN
directly:

<mn>3.14156&dots;</mn>

> 4. What is the best way to markup words in mathematical expressions that 
> represent units, identifiers, operators,...?
> With mi, mo or mtext? mtext is not rendered in a math font.
> Ex.:
> i. Area = 1/2 (base x height)
> ???
> <math>
> 	<mi>Area</mi>
> 	<mo>=</mo>
> 	<mfrac>
> 		<mn>1</mn>
> 		<mn>2</mn>
> 	</mfrac>
> 	<mo>&it;</mo>
> 	<mfenced>
> 		<mrow>
> 			<mi>base</mi>
> 			<mo>&Cross;</mo>
> 			<mi>height</mi>
> 		</mrow>
> 	</mfenced>
> </math>

I would do it just as you have with <mi>'s.  In your example, base and
height are really variable names, and thus should be mi's.  Since they
both have multiple characters, they should be typeset in a normal font
anyway.  

> ii. 150 m of fencing = 3 widths and 2 lengths
>       150 = 3w + 2L
> ...
> ???
> <math>
> 	<mtable groupalign="right center left">
> 		<mtr><mtd>
> 			<maligngroup/><mn>150</mn>
> 			<m?>m of fencing</m?>
> 			<maligngroup/><mo>=</mo>
> 			<maligngroup/><mn>3</mn>
> 			<mo>&it;</mo>
> 			<mi>widths</mi>
> 			<mo>and</mo>
> 			<maligngroup/><mn>2</mn>
> 			<mo>&it;</mo>
> 			<mi>lengths</mi>
> 		</mtd></mtr>
> ...
> 	</mtable>
> </math>

This works for me too.  I guess I might put the "and" in an <mtext>,
since it is sort of in the gray zone between a genuine mathematical
"and"  operator and the ordinary word.  Also, the typesetting for an
<mtext> is likely to be better.

> 5. mo: Invisible operators. Will you define an <mo>&InvisiblePlus;</mo> 
> to markup a fraction like 1 1/2 (one and an half)?
> If not, how do you propose to markup the implied plus in this
> fraction?

You wouldn't ask it you knew the battle we've had over
InvisibleTimes...  I think the only way to mark this up for
presentation is a <mn> next to a <mfrac>.  Not very satisfactory, I
realize.  

> 6. When explaining mathematics, it is often useful to present the 
> different notations used around the world. Is there an attribute or a 
> markup to specify the cultural domain notation we wish to render?
> 
> 
> Ex.<p>The decimal system of numbers, based on 10, is used in most 
> countries in the world. The notation for decimal points is not the same 
> in all countries, however. In Canada and the USA, the point is placed on 
> the line. In the United Kingdom, it is placed above the line. In France, 
> a comma is used on the line instead of a point.</p>
> 
> p>As a student in France, you would convert the decimal number
> 	7,12
>   to a fraction.</p>
> 
> <p>In the UK, you would convert the decimal number
> 	7&middot;12
>   to a fraction.</p>

No, not really.  As you obviously know, there is a lot of stuff to do
in this area, and MML 2 didn't take it on.  For the time being, using
a private attribute or maybe the 'class' attribute on the <math> tag
is probably the best work around.

> 7. math. In the MathML2.0, there is a section for all markups, but I 
> didn't find the one which explains the root of mathematical expressions: 
> the math markup. Is there a specific documentation that could tell me 
> more about it (attributes, etc.)?

Yeah, the <math> element is documented separately in Chapter 7 of the
spec.  Chapter 7 deals with the issues of embedding MathML in other
markup, so the <math> element is described there.

--Robert

------------------------------------------------------------------
Robert Miner                                    RobertM@dessci.com
MathML 2.0 Specification Co-editor                    651-223-2883
Design Science, Inc.   "How Science Communicates"   www.dessci.com
------------------------------------------------------------------

Received on Tuesday, 24 April 2001 11:09:57 UTC