Re: Blank nodes must DIE! [ was Re: Blank nodes semantics - existential variables?]

On Wed, Jul 08, 2020 at 11:54:16AM -0400, Thomas Passin wrote:
> Here's what I am thinking of, and I'll talk about points, since that was the
> ...
> Or put another way, just because the same literal value is assigned to two
> nodes does not make them the same.  Is that literal value itself the "same"
> for both?  In some software it might be - if it's been memoized, for example
> - but that's normally an implementation detail, not something fundamental.

When I say that (1,2) is a true value, aka an immutable struct, your
answer is that two (1,2) values are not the same because, taking into
account the open world assumption, they could have a third dimension
(or some other attribute).

You write "the same literal value is assigned to two nodes, does not
make them the same".  Is it correct to rephrase that as follows ?

  p1 has_coords (1,2)
  p2 has_coords (1,2)

In that case I agree that nothing proves p1 and p2 are the same.

But what I am pointing at when I talk about an immutable struct is not
the above.

A better comparison would be "2002-05-30T09:00:00"^xsd:datetime, that
could be deserialized to (year: 2002, month: 5, day: 30, hour: 9,
minutes: 0, seconds: 0).

Would you say that the two literals
"1;2"^<http://mydomain.com/mytypes/tuple-of-two-integers> and
"1;2"^<http://mydomain.com/mytypes/tuple-of-two-integers> are
different things ?

Does it follow from the open world assumption that
"2002-05-30"^xsd:date and "2002-05-30"^xsd:date are different values
because one could append the time information and write
"2002-05-30T09:00:00"^xsd:datetime ?

I would think that the open world assumption applies to nodes, not to
values/literals. Am I missing something ?

-- 
Nicolas Chauvat

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Received on Wednesday, 8 July 2020 18:30:38 UTC