RE: What do the ontologists want

 
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: dehora
: >I think that these two are not at all the same:
: >
: >1: RDF reification is a technique to make statements about
: >statements.
: >
: >2: KR reification is a technique for objectifying a statement.
:
: pat hayes
: These seem to me to be clearly identical. Maybe you mean something 
: more by 'objectifying' than I do, but calling something an 'object'
: (or an 'entity') in KR simply means that it is considered to be in 
: the semantic domain of description, and this is exactly what is 
: implied by saying that one is making statements about it. Objects 
: *are* things that one makes statements about (actually, it would be
: better to say, things that one could make statements about, but
thats 
: a technical quibble.).
: 
: Maybe you could elaborate on what you see as the distinction here?

I'll try. I made 2 mistakes at least. First (my bad), I should have
said this:

2: KR reification is a technique for objectifying relations.

Second, I mixed up reification and mentioning (and then proceeded to
waffle on about the difference...oh dear). Though I claim that this
is easy to do in RDF. 

I don't know enough to say whether reification itself is a dud for
RDF. In my KR102 class and in the 2 or 3 books I have that mention
reification, it came across as a technique to allow a language to
refer to its categories which are sometimes treated as predicates,
like dotcom(shop.com), and offers a trick that allows you to say
titsup(dotcom, shop.com) and treat the predicates as terms in the
language. And stuff like genus/inheritance using isa() and ako()
becomes available as you go. Now, I don't think RDF statements are
categories that can be treated like this for the most part, which is
why I say that reification over them isn't like KR reification. Then
again, I found KR102 tough going. However my real beef as an
implementer is with the 4 triples that make up an RDF reification,
not with the use of a URI acting as a reified statement. 

How about this; all imho:

1: RDF reification is a technique that turns statements into URIs.
2: KR reification is a technique that turns predicates into terms.

in RDF:

3: a statement is not a predicate.
4: a statement is not a resource.
5: a predicate is a resource.
6: a resource clearly doesn't need to be reified to have a statement
made about it.
7: excluding literals, things that are not resources cannot have
statements made about them.
8: a reified_statement is a resource.
9: a _reification consists of 4 statements, which share a
reified_statement. 

so I'm inclined to say:

10: RDF and KR reifications are not the same or at least not
operating on the same stuff.
10.a: a _reification is not an object.
10.b: a reified_statement is an object.

and inclined to believe that:

11: I want to be able to nest statements, especially queries.
12: I want to be able to hang properties off statements.
13: I might want to reify statements. Who knows.
14: I'd like to mention a statement with having to make a
_reification.
15: I'd like to reify a statement with having to make a _reification.
16: I'd like to hang properties off a statement with having to make a
_reification.
17: I'd like to be able to get my software to easily distinguish
between 15,16,17.
18: Bookkeeping _reifications in software is a hassle I could live
without.
19: In fact the thing I like least about RDF as an implementer are
_reifications.
20: I've suggested a tacky way to avoid _reifications using literals.
21: Jonathan Borden's query syntax proposal has better articulation,
has real legs.


regards,
Bill

- ----
Bill de hOra : InterX : bdehora@interx.com 



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Received on Thursday, 17 May 2001 20:59:22 UTC