Re: RM formalism supporting partial information
Date: Thu, 15 Nov 2007 15:31:19 -0800 (PST)
Message-ID: <f9cb29c9-cd77-4ddb-8d66-5da338d41562_at_l22g2000hsc.googlegroups.com>
On 15 nov, 20:11, David BL <davi..._at_iinet.net.au> wrote:
>
>
> I'm sure your time is precious and I don't want to be presumptuous,
> but have you digested much of the document? Do you have any
> particular comments on the operators, such as the information
> comparison operator which gives a partial ordering and a concept of
> information equivalence?
It's actually not a partial order, but a preorder because it is not antisymmetric. It's also a bit strange in that it says that the following relation bodies (for simplicity the tuples are unlabeled) all have the same information:
- { }
- { ({}, {}) }
- { ({a}, {}) }
- { ({}, {b}) }
It's also not clear to me why you take in the definition all projections over all subsets of the header. Why project at all?
But far more problematic is that you don't give any intuition for what this "information content" means. Just having an elegant definition and some cute mathematical properties is not enough. Is the information content what the "real meaning" of the nested relation is? But if the real meaning is a flat relation, then why bother at all with nested relations?
> 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?
As is probably clear by now, I'm still not really convinced that this interpretation is really so straightforward.
- Jan Hidders