Re: complementOf -> viewOf: proposed text

Hi Stian,
Your example really helps in fleshing out the multiple issues that are
unfortunately being mixed up (in my view), comments are inline:

entity(customerOnRedChair, [prov:location="the red chair in the cafe"])
>
This is a "class" definition (defining a category of resources/entities -
as used in maths (sets), logic etc.)



> entity(paoloInCafe)
> entity(stianInCafe)
>
These may be classes (with individuals corresponding to all the times that
paolo or stian are in cafe) or individuals as required by an application.



> entity(paolo)
> entity(stian)
>
> These are all "individuals" (not a category of resources as
"customerOnRedChair") - these are members of the sets/classes.

I believe you mention this distinction between class and instances in one
of your later mails.


> specializationOf(paoloInCafe, paolo)
> specializationOf(stianInCafe, stian)
>
> I think this construct hides many complexities and is incorrect according
well-defined specialization-generalization relationship in logic,
programming languages, maths etc. For example a person is a not a
specialization of the same person in different situations (and neither are
the descriptions/records about that person) :)

I agree with James that many of the examples discussed before your mail
were referring to attributes descriptions and not entities.

There are two ways of interpreting the above assertions:
a) when paoloInCafe is a class (described above) - then the above construct
is incorrect as it is mixing "types" (asserting class to be specialization
of an individual)

b) when paoloInCafe is an individual - then again the above construct is
incorrect as specialization is asserted between classes and not individuals



> alternateOf(paoloInCafe, customerOnRedChair)
> alternateOf(stianInCafe, customerOnRedChair)
>
>
> but we probably don't want to then infer:
> alternateOf(paoloInCafe, stianInCafe)
>
> and certainly not:
> alternateOf(paolo, stian)
>
> The above mentioned mixing of types paves the way the following
(seemingly) incorrect inference. I disagree with Paolo that the incorrect
inference is due to absence of time from the above examples.

Thanks.

Best,
Satya


> .. neither did overlap the old characterisation intervals, and are
> different 'things' in the world.
>
>
> however, if Paolo and Stian did not sit anywhere else but in the red
> chair, we can also have:
>
>
> specializationOf(paoloInCafe,
> customerOnRedChair)specializationOf(stianInCafe, customerOnRedChair)
> this implies that for the duration of paoloInCafe, it was also
> customerOnRedChair.
>
> --
> Stian Soiland-Reyes, myGrid team
> School of Computer Science
> The University of Manchester
>
>