[Om3] three avenues for the condition elements

[Michael Kohlhase]

Dear all,

now, also Paul has given his preferences. And ....

there are no time slots that all of us can make. The best slot seems to 
be Thursday 15-16 CET, unfortunately, I will very probably not be able 
to make this date. Therefore I suggest that I will try to juggle dates 
and someone else does the organization.

Michael

Michael Kohlhase wrote:
> Dear all,
>
> we should make progress on this, I have made a doodle for deciding on 
> a teleconference date, please give me your preferences at
>
> http://www.doodle.com/txbc7ez6gt5ahkzm
>
> The earlier in the week we talk the better.
>
> Michael
>
> Professor James Davenport wrote:
>> On Sat, October 25, 2008 5:17 am, Michael Kohlhase wrote:
>>  
>>> the MathML WG has to bring out the next working draft of the MathML3
>>>     
>> recommendation and we have a code freeze on November 6. Since this is
>> the last working draft before the "last call" stage of MathML3, it would
>> be good to have resolved the question whether the <condition> element
>> belongs into strict MathML or pragmatic. Therefore I would ask you to
>> give your opinions about the resolution ASAP. I will organize a
>>  
>>> teleconfere later in the coming week or early in the week of the 6.
>>>     
>> where we take a decision.
>> A good idea. I apologise for the delay in not following up on the teleon
>> of 10th - as usual I was overtaken by teaching before I had a chance to
>> finish the follow-up - I attach the current state for what it's worth.
>> [second thoughts - it wil probably fall foul of the length limit: I 
>> attach
>> the LaTeX, and the PDF (which may be further updated if I get a chance
>> today), is at http://staff.bath.ac.uk/masjhd/Conditions-JHD.pdf]
>>  
>>> Paul Libbrecht wrote:
>>>    
>>>> (warning: this text contains unicode character)
>>>> #1 condition element
>>>> Basically add, in OpenMath and strict MathML, an element called
>>>>       
>> condition or omcond that mimics the current condition element.
>>  
>>>> #2 condition symbol
>>>> Invent a new symbol called condition which would do a very similar
>>>>       
>> function.
>>  
>>>> For example, if it was called c, one would write a conditional
>>>> function as
>>>>   λ.x,y: c(x ≠ y, x / (x-y) )
>>>>       
>> My fundamental objection to MathML's condition, which I think applies to
>> both #1 and #2, is that its presence affects the semantics of the
>> surrounding objects. Indeed, I do not even no of a formal statement 
>> about
>> how far its influence might spread: it is sufficient to inspect all the
>> direct children of X for a condition element, or must one delve deeper?
>>  
>>>> #3 conditional symbol variants
>>>> For each binder-like symbol, add a variant symbol which does accept an
>>>>       
>> extra argument, the condition. The function above would be written:
>>  
>>>>   λ.x,y: x ≠ y, x / (x-y)
>>>>       
>> To do this neatly, one would have to scrap the rule that OMBIND only 
>> takes
>> one 'ordinary' child, but this, I think, is a small price to pay. 
>> Indeed,
>> if it is felt to be too high, one could add OMBINDCOND, with two
>> 'prdinary' children, the first as in OMBIND and the second the 
>> condition.
>> This would rescue MK's DEFINTCOND from the objections in my attached 
>> note.
>>
>> James Davenport
>> Hebron & Medlock Professor of Information Technology
>> Formerly RAE Coordinator and Undergraduate Director of Studies, CS Dept
>> Lecturer on CM30070, 30078, 50209, 50123, 50199
>> Chairman, Powerful Computing WP, University of Bath
>> OpenMath Content Dictionary Editor
>> IMU Committee on Electronic Information and Communication
>>
>>
>>   
>

-- 
----------------------------------------------------------------------
 Prof. Dr. Michael Kohlhase,       Office: Research 1, Room 62 
 Professor of Computer Science     Campus Ring 12, 
 School of Engineering & Science   D-28759 Bremen, Germany
 Jacobs University Bremen*         tel/fax: +49 421 200-3140/-493140
 m.kohlhase at jacobs-university.de http://kwarc.info/kohlhase 
 skype: m.kohlhase   * International University Bremen until Feb. 2007
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