- From: Iovka Boneva <iovka.boneva@univ-lille1.fr>
- Date: Mon, 16 Nov 2015 09:36:30 +0100
- To: public-data-shapes-wg@w3.org
Le 13/11/2015 19:33, Peter F. Patel-Schneider a écrit : > On 11/11/2015 07:50 PM, Arthur Ryman wrote: > [...] >> Iovka said that the draft is no longer being maintained. Her latest >> version of the semantics of ShEx is given in [1]. I pointed out that I >> had proposed a different approach to positive recursion. [2] >> >> We agreed to look at each others articles and decide how to proceed. >> >> [1] http://arxiv.org/abs/1510.05555 >> [2] http://arxiv.org/abs/1505.04972 > [...] > > I am continuing to look at [1]. > > > > It appears to me that ShEx there is *not* built on top of RDF, as the notion > of a graph there allows triples whose predicate is the inverse of a property. > This permits a different set of graphs than does RDF because the three graphs > below are different > > 1/ > :a :p :c . > :c ^:p :a . > > 2/ > :a :p :c . > > 3/ > :c ^:p :a . > > I am puzzled as to why this change was introduced. This is not a change, just an abstraction on RDF graphs. Because 2/ and 3/ and not abstraction of any correct RDF graph, they will never be considered. > > As well, there appears to be a single designated value for all blank nodes, so > that it is not possible to distinguish between > > 4/ > :a :p _:b1 . > :a :p _:b2 . > _:b1 :p :c . > _:b2 :p :d . > > and > > 5/ > :a :p _:b1 . > :a :p _:b2 . > _:b1 :p :c . > _:b1 :p :d . > In the abstraction, nodes still have unique identifiers, and two blank nodes are not the same. The 4/ and 5/ graphs above will be distinct, because in 4/ there will be two different nodes for _b1 and _b2, that are n_b1 and n_b2, respectively. The fact that val(n_b1) = val(n_b2) = _b is not a problem, because in ShEx there is nothing to distinguish between the local ids of two blan knodes anyway. -- Iovka Boneva Associate professor (MdC) Université de Lille http://www.cristal.univ-lille.fr/~boneva/ +33 6 95 75 70 25
Received on Monday, 16 November 2015 08:37:09 UTC