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Web Semantics of Datasets (v0.2)

From: Sandro Hawke <sandro@w3.org>
Date: Mon, 10 Oct 2011 07:30:01 -0400
To: public-rdf-wg <public-rdf-wg@w3.org>
Message-ID: <1318246201.2111.39.camel@waldron>
Here's some revised wording for the proposal, getting a bit closer to
spec text.   It's still somewhat informal, and mixing normative and
non-normative bits, and best-practice.   And it's not as clear as it
should be about handling change over time.

    -- Sandro
===
  A dataset D is true iff (1) its default graph is true and (2) for
  every pair of <N,G> in D, N names something (a "resource", sometimes
  called a "g-box") which, at every time T in R, has G as its current
  state.

  It follows from AWWW that if N is an IRI which can be dereferenced,
  a successful, correct dereference of N at any time T in R must yield
  a serialization ("representation") of G.

  In order to know whether a dereference occurs at a time in R, it is
  useful to have R declared in the default graph of D, or in another
  nearby, easy-to-find data source.  Where possible, is is helpful to
  have R be All Time; that is, having N name a resource whose state,
  by definition, never changes.

  In RDF data, N may be used (1) directly, to name the g-box,
  expressing things like the license that applies to its state, or who
  controls it; and (2) indirectly, to refer to G as the current state
  of the g-box.  Indirect reference can be used to express things
  about an RDF Graph (a "g-snap"), like that it was the graph some
  entity asserted at some time.  Indirection is done in the semantics
  of the predicates with which N is used.

  When N is used indirectly, the reference to G only holds inside time
  range R, of course.  Care must be taken not to use N as if it
  necessarily referred to G, outside of R.  Since R is defined to be
  the same for all elements of D, indirect reference is safe in the
  default graph.   
Received on Monday, 10 October 2011 11:30:13 GMT

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