Re: General semantics

From: paul c <>
Date: Fri, 21 May 2010 15:02:05 GMT
Message-ID: <NfxJn.4370$Z6.3289_at_edtnps82>

Nilone wrote:
> On May 21, 1:38 pm, Erwin <> wrote:

>> On 21 mei, 12:45, Nilone <> wrote:
>>> On May 21, 7:57 am, Clifford Heath <> wrote:
>>>> paul c wrote:
>>>>> By unary relation I mean a relation with one attribute (which I think is
>>>>> pretty standard lingo, surprised that anybody here wouldn't think that)
>>>> Right, that's what I thought you meant. In which case, it could be a
>>>> representation of either an existential fact type (an object type),
>>>> or a unary predicate over one. The distinction is important. A unary
>>>> predicate creates a subset of the object type it involves.
>>>> This distinction was, I believe, the cause of your earlier disagreement.
>>>> Further, a unary fact type does not have to be mapped as a unary relation.
>>>> It could be represented as a boolean value in a table of that object type.
>>>>> but I have no idea what a 'fact type' is.  I know of relation and tuple
>>>>> types but don't know what use terms like 'fact type' or 'unary fact'
>>>>> terms might have.
>>> Perhaps, fact type = intension while unary fact = proposition
>> Instantiating a predicate with attribute values always yields a
>> proposition, no matter what the degree of the relation is.

> Thanks for the correction. Let me try again: it seemed to me that
> Clifford's unary fact types correspond to propositional functions,
> while his unary facts correspond to the propositions yielded by
> instantiating such a type. As such, I see no real argument between
> the models; in fact, the little I know of ORM (mostly from looking at
> Halpin's page a while back) seemed to match up with the relational
> model well.

Tell us why we need more 'correspondences'. Received on Fri May 21 2010 - 17:02:05 CEST

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