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Equality/equivalence of URIs

From: Johann Petrak <johann.petrak@chello.at>
Date: Thu, 18 Aug 2011 20:43:31 +0200
Message-ID: <4E4D5D53.1030609@chello.at>
To: public-owl-dev@w3.org
Hi all,

(please excuse if this is not the correct list to ask this
question, I was pointed to here on the protege-owl list.
I would be grateful if you could point me out to a better
list in that case)

I am puzzled about what the standards say about when and
how two URI references used in an OWL ontology
should be considered to be equal / equivalent:

As an example:
 a) http://some.org/#%C3%B6
 b) http://some.org/#%c3%c6
 c) http://some.org/

Do the standards *require* somewhere that e.g. the two
versions a) and b) should be treated as the same URI when
encountered somewhere on the semantic web or when used
in a SPARQL query (the reality seems to be that they are
treated as not equal, but is this not dangerous for the

How is equality defined between URIs and IRIs as in c)?
If the URI is using a hierarchical scheme what is required
or defined with regard to path elements like "../../" or
parts of the scheme like user auth or port number?

Nearly all URIs for languages other than english need some
characters not in the ASCII set so this is a frequently
to solve problem, I guess?

Received on Friday, 19 August 2011 08:03:58 UTC

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