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Re: multisets everywhere

From: Anthony Moretti <anthony.moretti@gmail.com>
Date: Tue, 21 Dec 2021 09:51:22 +1030
Message-ID: <CACusdfR+roGJHPJhYm-P1REBj=5vdZszV_JoHvZk4kskN4f=1g@mail.gmail.com>
To: thomas lörtsch <tl@rat.io>
Cc: Laufer <carlos.laufer@gmail.com>, "public-rdf-star@w3.org" <public-rdf-star@w3.org>
On Tue, Dec 21, 2021 at 12:18 AM thomas lörtsch <tl@rat.io> wrote:

> Am 20. Dezember 2021 12:33:59 MEZ schrieb Anthony Moretti <
> anthony.moretti@gmail.com>:
> >Hi Thomas
> >
> >I highly doubt that defaults like "the beginning of time" and "everywhere"
> >> are very helpful in practice
> >>
> >
> >Aren't the default values the assumptions that already have to be made
> >though?
> No, I don't think so. Nobody thinks that marriages between mortals last
> eternally.

And it's exactly for that reason I believe marriage statements would
benefit from start and end time positions.

> >OTOH they would require annotating statements that are NOT valid
> everywhere
> >> and anytime to explicitly say so even if they had otherwise no need to
> >> state such constraints
> >>
> >
> >But why would they have no need? If they're not valid everywhere and
> >anytime isn't that important to state?
> Why would you want to force people to state the obvious?

I really don't, those positions should be left blank if the default values
are being assumed. If the statements aren't valid everywhere and anytime
then that's important to know when merging graphs for example.

Come to think of it, leaving a position blank would simply mean "unbounded":

 - Start time (assumption if blank: unbounded)
 - End time (assumption if blank: unbounded)
 - Location (assumption if blank: unbounded)
 - Certainty (assumption if blank: 1.0)

Any statement is implicitly lower bounded by the earliest time that both
the subject and object exist.

More generally, basic temporal logic says that the bounds on any event are
the bounds for its subevents and the subevents can be explicitly bounded
further. If statements represent relationships and relationships are events
then the statement is a subevent of the existence event of both the subject
and object, therefore any statement can leave those positions blank but
still have bounds, temporal and spatial.

> > The positions can be left blank if
> >current assumptions are maintained so that would probably mean most
> >statements can be left untouched, and if the assumptions are different for
> >the entire graph they could be stated at the graph level.
> I don't understand. If they can be left blank and consequently not
> asserted, how are they defaults?

Any reasoner would assume "unbounded" if no values are provided.

> >Better to start from a principled approach and then see how hard it has to
> >> be tweaked to arrive at a practical solution, accomodate corner cases
> etc.
> >>
> >
> >Feel like that's what I'm doing, haha.
> If you propose to solve a problem that I describe as a very general one by
> some examples of seemingly common cases you narrow the scope. That
> narrowing has to be well understood. Maybe my perspective clouds my
> judgement but my feeling is that your proposal narrows the scope in quite
> ad hoc ways that might solve the problem for some special cases (and even
> there I have my doubts as mentioned above) but leaves a lot or most of them
> (even equally general ones like authorship) unresolved.

If I'm understanding you correctly, I agree that a referentially opaque
relation such as "statementOf" is still needed for provenance use cases
etc., is that what you mean when you're talking about authorship? But the
need for a referentially transparent relation, and the subsequent confusion
that ensues, would be greatly reduced if statements could have start and
end time positions.

It also addresses the multiset problem because statements with the same
subject, object and relation but different start and end times etc. are
different statements.

Received on Monday, 20 December 2021 23:21:47 UTC

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