W3C home > Mailing lists > Public > public-webarch-comments@w3.org > January to March 2004

WD-webarch-20031209: The vastness of URI space

From: C. M. Sperberg-McQueen <cmsmcq@acm.org>
Date: 05 Mar 2004 00:15:46 +0100
To: W3C TAG mailing list <public-webarch-comments@w3.org>
Message-Id: <1078442146.2531.21.camel@localhost>

Section 2 para 3 says

    When a representation uses a URI (instead of a local identifier)
    as an identifier, then it gains great power from the vastness of
    the choice of resources to which it can refer. 

This suggests that URIs have the advantage, compared to local
identifiers, of being more numerous.  But if we assume that both URIs
and local identifiers are finite-length strings without any length
restriction we need worry about, then both sets are enumerably
infinite and there is a one-to-one mapping between them, so that they
have exactly the same cardinality and neither is any more vast than
the other.

I suspect that what is meant here is that URIs have the advantage of
being dereferenceable; this is true of some URIs, but not, I think, of
all.
Received on Thursday, 4 March 2004 18:16:37 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 6 April 2009 12:37:30 GMT