Re: RM formalism supporting partial information

On Nov 15, 10:01 am, Marshall <marshall.spi..._at_gmail.com> wrote:
> On Nov 14, 2:21 pm, David BL <davi..._at_iinet.net.au> wrote:
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> > On Nov 15, 1:20 am, Bob Badour <bbad..._at_pei.sympatico.ca> wrote:
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> > > paul c wrote:
> > > > David BL wrote:
> > > > ...
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> > > >>http://www.members.iinet.net.au/~davidbl/MVattributes.doc
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> > > >> This is still a work in progress.
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> > > >> I welcome any comments.
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> > > By the second paragraph, the document entered into the realm of
> > > nonsense, and I stopped reading.
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> > An attribute has a name and a domain. How is that nonsense?
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> You didn't say an attribute *has* a name and a domain. You said
> an attribute *is* a name and a domain. So you can have two
> different attributes with the same name.

I said an attribute *consists* of a name and a domain. That is compatible with saying an attribute has (and only has) a name and a domain. I assume you're not making some philosophical point about the sum being greater than the parts; IMO distinguishing between "has" and "is" is splitting hairs. In natural language at that!

Seeing as you're likely to try to interpret mathematical structures in terms of words like "has" and "is", I must point out that mathematical structures do not exclusively own their "parts". For example the point (10,15) in R^2 doesn't exclusively own the integers 10,15 (ie they can be used for other things!). Similarly an attribute doesn't exclusively own it name or its domain. In keeping with the spirit of mathematical formalism I didn't say that an attribute has a domain-name - instead it has a domain. Formally that only means there exists a mapping D from attribute x to domain D(x).

You cannot state that all attributes have different names. That would be nonsensical because universal quantification is only meaningful with respect to some defined set over which it quantifies. At the point of definition of "attribute" there is no such set to quantify over. I find it curious that you appear to allow a mathematical realism philosophy to invade mathematical definitions.

In the document I (correctly) said nothing about unique names until defining a relation. Received on Thu Nov 15 2007 - 06:12:16 CET