# Re: RM formalism supporting partial information

Date: Thu, 15 Nov 2007 11:11:26 -0800 (PST)

Message-ID: <4901ca0f-4f81-4ede-a99a-6adabf00ab23_at_i29g2000prf.googlegroups.com>

On Nov 16, 2:54 am, Jan Hidders <hidd..._at_gmail.com> wrote:

> On 14 nov, 14:47, David BL <davi..._at_iinet.net.au> wrote:

*>
**> > Nearly two weeks ago I posted to the thread "atomic" regarding a join
**> > operator I had defined back in January. A discussion with Paul C
**> > inspired me to more carefully develop the mathematical formalism.
**>
**> The mathematical formalism is not your biggest problem, altough it
**> could certainly be improved (if you want I might be tempted to help),
**> but what seems to be missing is a decent understanding of what all the
**> math exactly means. What is the intuition behind your approach? Why
**> would it make sense? You hint at this with the interpretation function
**> I, but this should not be a side remark in the middle but rather the
**> foundation and justification of the rest, and that doesn't seem to be
**> there.
*

I agree the document leaps straight into the maths without properly stating the objective, and I don't consider it in any way suitable for publication. I wanted to talk about the meaning and purpose on cdt, and the document was really more like a "dumping ground" because directly posting that stuff wasn't a good option.

You are correct that the interpretation function I is the "foundation and justification of the rest".

I would certainly be interested in any suggestions on how to improve the mathematical formalism. Perhaps you could post an example of what you have in mind.

I posted a work in progress in the hope that someone could offer some opinions - perhaps before I wasted too much time buried in the proofs. I would say as well that I regard the exercise as exploratory, and therefore it is difficult to say for what it might be useful without first discovering all the properties of the operators.

> It will not suprise you to learn that the use of the nested relational

*> model as a representation for uncertain data is not really a new
**> thought. I could give references, but you may want to Google yourself
**> first, or maybe not because it might spoil the fun.
*

I've read about RVAs in ch 19 of C.J.Date's Introduction to Database Systems, as a possible solution to missing data. Is that what you are referring to?

> You may also want to Google my name, to see why I think I can get away

*> with being so arrogant. ;-)
*

I don't think you're being arrogant at all.

> > There is far too much detail to post. The following is a link to a MS

*> > word document.
**>
**> >http://www.members.iinet.net.au/~davidbl/MVattributes.doc
**>
**> A final tip. Decent database theory doesn't come in Word. It comes in
**> LaTeX. :-)
*

The union and intersection operators I defined appear to have nice properties and a straightforward interpretation. This seems to contrast with outer intersection and outer union. Does that suggest there could be something useful in the approach? Received on Thu Nov 15 2007 - 20:11:26 CET