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RE: motivation for bNodes/existentials in RDF; note for parsers

From: Jos De_Roo <jos.deroo.jd@belgium.agfa.com>
Date: Mon, 25 Mar 2002 20:43:15 +0100
To: massimo@w3.org
Cc: ""Dan Connolly" <connolly" <connolly@w3.org>, ""Pat Hayes" <phayes" <phayes@ai.uwf.edu>, "<w3c-rdfcore-wg" <w3c-rdfcore-wg@w3.org>, ""Lynn AndreaStein" <las" <las@olin.edu>
Message-ID: <OF9EA450E5.1B253282-ONC1256B87.006AD83E@agfa.be>

[...]

> I think what concerns me most, in this context, is the appropriate
> explanation of why this is the choice to make, versus the most
> obvious choice we have at our disposal (i.e., skolemization).
> That is, what are the pro's and con's that favour the existential
> approach vs the skolem one?

well, bNodes are quite all-round I think
- in an graph with asserted facts they are existentials
  which could be written as skolem constants, indeed
- in a query (graph) they are universals
- in the LHS (graph) of an entailment they are universals
- in owl lists the are functional terms
  i.e. (a b) denotes the same thing wether it's
  written in one graph, or written in another graph
- in the RHS (graph) of an entailment they are skolem
  functions which could be written as daml lists (I think)

--
Jos De Roo, AGFA http://www.agfa.com/w3c/jdroo/
Received on Monday, 25 March 2002 14:44:11 EST

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