Re: How do you deprecate URIs? Re: OWL-DL and linked data

On Jul 8, 2008, at 11:39 PM, Peter Ansell wrote:

> 2008/7/9 Bijan Parsia <bparsia@cs.man.ac.uk>:
>> On Jul 8, 2008, at 10:45 PM, Peter Ansell wrote:
> <snip>
>>> Why doesn't the
>>> owl spec define these cases which are very clearly the first step  
>>> for
>>> trying to reason with an externally defined object as if it were a
>>> locally defined one?
>>
>> OWL has no distinction between external and local.
>
> Maybe this is an issue that needs to be addressed, as people who want
> to get into the semantic web will never want to deal with it all at
> one time as if it is "local".

But that's a silly reading of what I said. Obviously, it's not the  
case that the whole semantic web gets pulled into every OWL ontology.  
But an ontology is a set of axioms, period. Any additional munging or  
contextualization or mapping happens at another level.

> For obvious computational reasons, but
> also for practical reasons, people as you say below, deal with issues
> incrementally, in small steps.

I think you should consider asking questions before attacking straw.

[snip]
>>> If people want a term that they can use without owl reasoning to
>>> define useful real-world-identity based mappings
>>
>> sameAs isn't an identify based mapping, it is *identity*.
>
> Can sameAs be used to say that structurally different objects have the
> same identity?

If you say that a sameAs b, there's only one object, not two. Their  
structure now is unioned.

> Formally "identity" might be well defined in the local
> ontology but that doesn't mean a human will agree with it in their
> open world attitude.

I have no idea what an open world attitude is.

[snip]
>>> If they aren't being shown
>>> anywhere and no one in the any semantic group
>>
>> Aren't they part of a semantic group?
>
> Maybe real world people

Pfft. Puffing yourself up that way doesn't help your argument content.

> who don't study semantics for a living might
> want to do something with RDF or OWL...

My complaints about sameAs championing are to semantic groups who say  
that people should use that instead of coming up with better tools.

> A dream I know but it will
> make us look so much cooler.

Somehow, I doubt this will help.

>>> is giving them
>>> directions they will continue to use the one that everyone else is
>>> using, ie, sameAs, much to a traditionalists disgust I expect.
>>
>> Meh. Your use of traditionalist in a pejorative sense isn't helpful.
>
> Sorry, just trying to highlight the fact

Hmm. It's still not a fact, just insult.

> that a core group of semantic
> type academics

Grow up.

And I'm still in the room, by the way.

> don't want to acknowledge or provide alternatives for a
> gap which could,

See where I said there was a gap.

> if warnings about not using owl:sameAs liberally are
> real,

Did I ghostly stutter or something?

> actually break down the whole idea when one wants to move from
> their little local ontology to a distributed semantic web.

Dood. There are technical problems with sameAs if you want to use  
more expressivity. It also has the wrong expressivity for a lot of  
mapping purposes. People who say, "Oh use sameAs" aren't providing a  
solution, they are just giving bad advice (imho). My suggestion would  
be that people concerned with this topic work on providing an actual  
and robust solution.

Complaining that the Big Nasty People Who Know What They're Talking  
About are raining on your sameAs parade isn't constructive. Perhaps  
your should direct your bile toward people who claim that sameAs is a  
solution.

>> First, people *do* use sameAs for the semantics (to some degree).  
>> But often
>> those semantics are wrong. People champion that use. I think that's a
>> mistake. It can seriously bite you on the butt as you add more  
>> expressivity.
>> If you don't ever use more expressivity it won't (perhaps).
>
> How do you propose people should be able to generically say that two
> URI's refer to the same real world thing if their representational
> data structures

You lost me with your jargon.

> are fundamentally disjoint and hence saying owl:sameAs
> will break something somewhere at some point in time?

That's not what I was concerned about.

> Do any of the
> OWL normative documents deal with this issue?

Frame the question concretely and intelligibly and perhaps I can help  
you.

>> One can only tackle so many issues at a time. I try to give some  
>> info so
>> people, instead of using what I think is the wrong thing, can  
>> figure out
>> something better.
>
> This is a big issue currently.

There are lots of issues. Many of them are big to many people. Why  
not try to solve some?

> What alternatives do you have to give them?

I'm not sure why you think that I shouldn't point out technical  
problems with using sameAs.

Cheers,
Bijan.

Received on Tuesday, 8 July 2008 23:12:09 UTC