Re: content for characters

On Wed, 20 Jun 2001, Robert Miner wrote:

> 
> > i was just wondering if there was a way to apply certain characters, for 
> > example "plusminus" or "plusmn" as content mathml as opposed to leaving it 
> > as presentation mathml since the symbol is not just a constant, but rather 
> > represents an operation.
> 
> This is kind of a tricky case.  The plusminus symbol is usually really
> used as a shorthand for  two separate operators.  One could try to
> define a plusminus operator that maps from RxR -> RxR, so that
> 
> 
>   3 plusminus 5 = (8, -2)
> 
> or something like that, but then you have problems extending all your
> other operators to work on lists, e.g what does (3 plusminus 5) * 2
> mean?  The * isn't ordinary multiplication anymore, since the operand
> on the left is now an ordered pair.
> 
> For content encoding, probably the better way to go is to use the
> logic contructs, or possible the list construct to write down both the
> result of adding and subtracting the arguments.  Thus, the presentation
> MathML
> 
> <mrow><mn>3</mn><mo>&plusmn;</mo><mn>5</mn></mrow>
> 
> best corresponds to a content encoding like
> 
> <list>
>   <apply><plus/><cn>3</cn><cn>5</cn></apply>
>   <apply><minus/><cn>3</cn><cn>5</cn></apply>
> </list>

This would be nice, though the ordering is artificial, it would be better
if we used/had some sort of tuple construct

> 
> <apply>
>   <or/>
>   <apply><plus/><cn>3</cn><cn>5</cn></apply>
>   <apply><minus/><cn>3</cn><cn>5</cn></apply>
> </apply>
> 

of course this should return a boolean, and in fact makes no sense when
applied to plus and/or minus, unless their meanings where overridden using
the 'definitionURL' attribute (what would that mean for 'minus'!),

Bill.

--

Received on Wednesday, 20 June 2001 17:06:08 UTC