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Re: A URI for your Favourite Pub: httpRange-14 Question

From: Giovanni Tummarello <g.tummarello@gmail.com>
Date: Sat, 23 Sep 2006 01:22:06 +0200
Message-ID: <210271540609221622m67535d64rfed03af5c1f2a40c@mail.gmail.com>
To: "Richard Newman" <r.newman@reading.ac.uk>
Cc: semantic-web@w3.org

Hi there :-)

> > so .. since its given in the semantics that second part is a URI
> > then one is free to dereference the second part and fall back
> > into the usual scenario.. but with no ambiguity.
>
> ... except that it is ambiguous. If I say
>
> <http://mydomain.com/slashdot>
>
> I control what I mean. Your reuse of my identifier is an implicit
> contract (at least, that's how ontologies work -- this agreement
> gives them their mapping into the real world). However, if both you
> and I visit Slashdot at the same moment, we end up with the same tdb
> URN. I'm referring to the community, you're referring to the business

Isnt that as ambiguous as any human readable description, includign
the comments which describe the terms of ontologies?

In case of badly selected URI (e.g. one that people are likely to use
for 2 different purposes which cannot be quickly disambiguated )
people would probably learn and move to les ambiguous URL. e.g.
tdb://9.23.2006:http://www.ostg.com/about/index.htm


>
> Compare and contrast with the tag URI.
>
> <http://www.taguri.org/>
>
> "The tag algorithm lets people mint  create  identifiers that no
> one else using the same algorithm could ever mint."
> Either use a tag URI or a bnode, and point to the describing page
> with an IFP. The semantics are clearer.
>

I am a fan of tag uri!
we support them in DBin (the first thing you get when starting up is a
proposed tag uri for you as a user). But they are to be used if you
want to make sure there is no possibility of collision. Talking about
pets, beers YOU brew etc. For any other (and most?) identification
purposes  you really want to "collide" with others.. that's the whole
point! :-) if you want to talk about peroni beer you better have a way
to make it that it is very likely that someoe else independelty come
up with the same identifier. I see a lot of advantages withthis for
the SW to pick up... and it fits TBL idea of "extending"

> > owner of the domain (there is no get call). Plus.. anyone can talk
> > aobut any URI .. who cares then if that doesnt exist?
>
> Well, you're minting into a shared URI space :)

If you only mint your own then put a bunch of "sameAs" would be the
same.. are we not allows to talk about URIs we dont own? Talking about
and minting sound the same to me ..

> Not necessarily, but it's recommended that dereferencing a URI
> returns an 'authoritative' description of that resource.

when the URL is hostd by someone who "owns the idea" .. +1 tdb

>

> > the semantic of it however allows one the
> > decide whether to ignore the date and smush on that.. or do
> > whatever else, also according to the "type".
>
> URIs are meant to be opaque. Better would be to use named graphs to
> provide a context so that the date, user etc. become explicit.


>From my understandign the "uri opacity" in the SW is somehow an
extension to a principle which is sound sound limited to HTTP only..

in HTTP uris uri opacity is clear and limited.. "dont you infer you're
about to receive a GIF just becouse the url ends in .gif.. look at the
mime type you get from the OTHER side when you make the get request".

In fact URIs are not opaque at all.. to clients.  the protocol part
gets decomopsed from the server.. the server gets DNS dereferenced,
the path gets requested in the GET , the ? get passed etc etc etc.
There is a percise semantics up to the point where a piece of URI is
to be used "as it is" as a parameter (that is as the parameter of the
get request) then its opaque!.

Why do we keep talking about on the sw? Once you explore/query
whatever you graph and you finally reach a URI, exactly as a web
browser decomposes the URL to resolve it a SW browser could use all
its knowledge about the semantics of the URI itself to provide the
service.. in this case making sure the meaning of the URI is well
understood!

Example.. if its a ISBN uri it could show you a page from your
favorite bookstore with prieces and comments about that book. If its a
URL.. well.. just invoke the system browser, if it is a tag URI, since
the specs say "put your email" then it could show a button which says
"email the minter and ask what he meant :-) "

Giovanni
Received on Friday, 22 September 2006 23:22:14 UTC

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