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Re: a question about <forall> element

From: Andreas Strotmann <Strotmann@rrz.uni-koeln.de>
Date: Tue, 06 May 2003 09:46:42 +0200
Message-ID: <3EB76862.5060006@rrz.uni-koeln.de>
To: Tim Bagot <tsb-w3-math-0003@earth.li>
CC: "'www-math@w3.org'" <www-math@w3.org>, Gang Du <GangDu@dessci.com>

<apply>
 <forall/>
 <bvar> <ci> x </ci> </bvar>
 <condition> <apply> <lt/> <ci> x </ci> <cn> 0 </cn> </apply> </condition>
 <ci> x </ci>
</apply>

is perfectly fine Content MathML stating what you requested.  It just 
doesn't have a reasonable meaning that I could figure out, but Content 
MathML was never meant to preclude stating silly things, or things that 
only make sense with additional context definitions.

The misunderstanding may be about <forall/> being required to be used 
within the context of an apply element.  That refers to the apply 
element within which the forall element is embedded, however, and 
therefore there is no problem if there is no apply element as a sibling 
of the forall element.

 -- Andreas

Tim Bagot wrote:

>At 2003-05-05T10:03-0700, Gang Du wrote:-
>
>  
>
>>In MathML 2 specification, content markup element <forall> must be
>>used in conjunction with one or more bound variables, an optional
>>condition element, and an assertion which should be an <apply>
>>element or a deprecated <reln> element. Consider the following
>>statement: "for all x, x < 0, x". Since the assertion here is
>>just a single variable, how to translate this into a valid content
>>markup? Or this is not a valid forall statement?
>>    
>>
>
>The last part is meant to be a predicate, so that's not likely to be a
>sensible forall statement. However, "forall x, x in X, x" might just be.
>Even so, that is really a pathological case, and I don't think it would
>be overly painful to apply the identity function.
>
>
>Tim Bagot
>
>  
>
Received on Tuesday, 6 May 2003 03:46:50 GMT

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