[whatwg] Mathematics in HTML5

Fri Jun 9 08:44:09 PDT 2006

Juan wrote:

> I think that markup would be more easy possible with posibility of
> ampliation, such that better authors could do a better job but average
> users could easily obtain results in a cheap and rapid way.

That's something very desirable, I think, as it follows the general  
spirit of HTML.

> I would disacourage any semantic markup and a focus only in structure
> (markup) and presentation (CSS with XSL-FO as second choice).
>
> In that case something like
>
> <frac>
>   <num>b</num>
>   <den>2</den>
> </frac>
>
> is structural.

Good observation. Semantics convey meaning, structure is about  
organisation. The example above convey the same meaning as b/2, b÷2,  
or "b divided by 2", but it is *organized* as a fraction.

It seems most of HTML focus on the structure, not semantics.  
Paragraphs, headers, blockquotes, tables, lists, and now sections and  
asides, are more about organisation than meaning. Others elements in  
HTML -- <q>, <var>, <kbd> -- are more on the semantic side. It seems  
to me that the semantic elements are the least common in usage, but I  
don't have any statistics to support that.

> I would not encourage usage of a type attribute. A simple class  
> would be
> sufficient and then we can reuse available CSS and HTML engines. The
> implementation of full semantics in browsers would be very, very  
> complex
> and nobody has proved that using type=“matrix” or type=“vector” the
> semantics can be unambiguosly encoded.

I agree completely. My suggestion of a type attribute had mostly the  
same purpose as class, and now I see no reason we should duplicate  
class.

Combine class with a profile with <head profile="..."> and you can  
give a semantic meaning to formulas through a microformat. It's a lot  
better than predefined semantics with some added fuzzy author semantics.

So I agree we should focus on ways to express the structures found in  
formulas and not the semantics, which should be left to  
mathematicians and scientists in their respective fields.

> For any array structure –matrix, vector, determinant or any other-  
> why do
> not simply reuse available HTML elements: <table>, <td>... instead
> proposing new ones <mr>, <md> doing the same? CSS rules could use
> different selectors
>
> body> table: CSS rules for text tables
>
> body> formula> table: CSS rules for text tables

I'm not sure about this. Tables have been overused before (for  
presentation) and it could be dangerous now to say to authors to use  
tables as matrices. That, and the fact that the word "table" already  
has some meaning, contains a caption and has the concept of header  
cell, makes me feel uncomfortable with this.

My idea was to use <matrix> as a generic element name for both  
matrices, vectors, determinants, as well as anything else that may  
fit. Maybe <array> could be a better, more generic, name for that.

> fences could be done as
>
> <fence left="round" right="square">expression</fence>

But isn't this presentational instead of structural? Why not use

     <fence class="parenthesis">...</fence>

with the proper CSS for presentation? I suppose one reason may lie in  
the non-obviousness of implementing different kinds of fences styles  
in CSS.

> The usage of external containers as <integral>, <sum>, <product>,  
> was done in previous versions of MathML code but abandoned in  
> recent proposals.

While I was the one who came some days ago suggesting the <integral>  
syntax you quoted, I somewhat concluded yesterday it was not worth  
it, because it does not fit the written language, nor LaTeX for that  
matter. So I suppose we now agree on that.

Michel Fortin
michel.fortin at michelf.com
http://www.michelf.com/