Re: Squaring the HTTP-range-14 circle [was Re: Schema.org in RDF ...]

* [2011-06-12 22:52:18 -0700] Pat Hayes <phayes@ihmc.us> écrit:

] OK, I am now completely and utterly lost. I have no idea what you 
] are saying or how any of it is relevant to the http-range-14 issue.
] Want to try running it past me again? Bear in mind that I do not
] accept your claim that a description of something is in any useful
] sense isomorphic to the thing it describes. As in, some RDF describing,
] say, the Eiffel tower is not in any way isomorphic to the actual
] tower. (I also do not understand why you think this claim matters,
] by the way.) 

So in the previous email, Danny used the important word - relevant.
Let's unpack that a little bit. Suppose we have no range-14 and all
these RDF statements out there are all mixed up about what they refer
to. Well, not completely mixed up. They're kind of clumped together,
web pages and the things they are about tend to get confused but
probably the chain of inferences that lead you to believe that the
Eiffel tower is a dog is pretty unlikely.

So there is some relationship between a description of the Eiffel
tower and the tower itself. The relationship is akin to similarity in
a very specific way - they are similar enough that someone thought it
made sense to write down that the tower was 356m tall. Unfortunately
they got confused and wrote down that the web page was 356m tall. No
matter, they are still different enough in the relevant ways that
anyone interested in heights on the order of hundreds of meters is
unlikely to be confused.

Same with the dog. Is the distinction between the dog and the picture
important to me? Maybe, maybe not. It depends what I'm trying to do.
If I want to make sure that I can recognise the doc when I meet her,
a picture or the actual dog might do equally well.

So that's the thing, similar or different in the relevant respects for
the purpose at hand. The purpose at hand is necessary to figure out
relevance. Just deriving all the possible things that can be entailed
from the information you have is no good. You have to derive the
relevant things in a particular context. You have to throw out givens
that are irrelevant to you or that lead you to irrelevant or
nonsensical entailments.

In the general case this is hard. It's not even clear if it is
relevance understood like this is computable. The intent of the user
is so clearly in the loop providing a reference frame for evaluating
relevance and capturing and representing a user's intent is not
something we have a good way of doing apart from hand-crafting
interactions.

Is it doable in simple cases (with rules programmed by humans) like
figuring out the foaf:knows graph where people and their homepages
can just be merged without too many bad side-effects.

We need a different kind of rule here - a cut rule. That says if
some condition obtains, *remove* some statements. For example,
remove all { ?doc a foaf:Document } before running the productive
rules might be a common one where we know that we aren't interested
in information resources.

Cheers,
-w

-- 
William Waites                <mailto:ww@styx.org>
http://river.styx.org/ww/        <sip:ww@styx.org>
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Received on Monday, 13 June 2011 20:52:13 UTC