Re: RM formalism supporting partial information

From: Marshall <>
Date: Sat, 24 Nov 2007 14:34:35 -0800 (PST)
Message-ID: <>

On Nov 23, 10:56 am, Jan Hidders <> wrote:


> Exactly, so in that sense it is actually complete, and you can make
> that claim precise. The set of tupels in the answer will be exactly
> the set of tuples that are certain to be in the result of the same
> query over the omniscient database. By the nature of the problem every
> query should actually return 2 sets of tuples: the set of certain
> answers, and the set of possible answers. Your operators should
> therefore not operator on relations but on pairs of relations.

It seems to me that anything that we can say about partial information can be said with total information. In other words, efforts at making the *system* understand partial information are merely pushing systemward calculations that could be done in a system without any understanding of partial information.

If so, it seems to me the best we can hope for with such an effort is some additional convenience. At which point, any justification for a system with built-in support for partial information *must* be done in terms comparing the convenience of queries, processing, etc. with vs. without the new partial-info primitives. I don't recall having seen this done however.

An analogous situation applies with approximate calculations.

I would be interested to hear anyone agree or disagree.

Marshall Received on Sat Nov 24 2007 - 23:34:35 CET

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