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John Cowan wrote:
> > 2. Is kilometer a function? e.g., kilometer(Yangtze) --> 6300
> > In general: kilometer(physical object) --> number
> > "The kilometer function maps a physical object to a number."
>
> I think this view is the most nearly correct, but it needs amplification:
> it doesn't capture that it's the *length* (rather than, say, the
> average depth) of the Yangzi that is 6300 km. So we can rewrite it
> in terms of relations as follows:
>
> Yangzi length X
> X kilometer 6300
>
> where "kilometer" is a relation that maps a length (an abstract property
> of a physical object) into a pure number.
So, kilometer is a function of this sort:
kilometer(length(Yangtze)) --> 6300
"kilometer is a function which maps the length of the Yangtze to 6300."
Another example:
kilometer(avg-depth(Yangtze)) --> 0.25
"kilometer is a function which maps the average depth of the Yangtze to 0.25."
The general case is:
kilometer(distance) --> number
where distance is an abstract dimension object.
How are functions represented syntactically in XML? Given the above
viewpoint, this form no longer seems appropriate:
<River id="Yangtze">
<length units="kilometer">6300</length>
</River
Perhaps a more faithful representation of:
kilometer(length(Yangtze)) --> 6300
is this:
<River id="Yangtze">
<length>
<kilometer>6300</kilometer>
</length>
</River>
Thoughts? /Roger
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