- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Wed, 11 Apr 2012 14:55:09 +0100
- To: Sandro Hawke <sandro@w3.org>
- CC: public-rdf-wg@w3.org
On 11/04/12 14:24, Sandro Hawke wrote: > On Wed, 2012-04-11 at 08:40 +0100, Andy Seaborne wrote: >> On 10/04/12 23:38, Sandro Hawke wrote: >>> Crawlers wont necessarily report all the data from each source. For >>> instance, they could quite plausibly truncate at 100MB source text. >>> >>> With 'complete-graphs' semantics, they would have to flag that fact in >>> the metadata somewhere; with 'incomplete-graph' semantics, then I expect >>> truncating crawlers wouldn't bother to flag it, since their report would >>> still be correct. >> >> RDF is monotonic. > > You might be overstating the case, but I certainly agree that it's best > to use monotonic logics and monotonic modeling with RDF. > > I mention this only because I have gotten pushback on this from time to > time. For instance, when I was developing the RIF-in-RDF mapping, which > lets one convey rules (and graphs) in RDF, I made sure the mapping was > monotonic. That is, I wanted to make sure that if some of the resulting > description triples were missing, it would not look like a complete > description of something which wasn't true. BUT several experts in RDF > in the RIF Working Group (eg Dave Reynolds, if I recall correctly) > argued that this was not a necessary feature. (We did end up keeping > it, though. http://www.w3.org/TR/rif-in-rdf/ > >> Adding some triple can not change the meaning of >> something else; it can only be a further restriction on the >> possibilities described. Can you show how adding a declaration of >> incompleteness of the graph semantics isn't breaking monontonicity? > > Sorry, I was using the term "flag" rather loosely. I don't mean a > separate triple which acts as a flag, but just some indication in the > dataset. > > Given the modeling and vocabularies used in > http://www.w3.org/2011/rdf-wg/wiki/Graphs_Design_6.1/Crawler_Example > > the flagging could be done monotonically by either using a different > class... > > [ a eg:TruncatedDereferenceOperation; > .... > ] > > or a different property: > > [ a eg:DereferenceOperation; > ... > eg:partialResult ... > ] > > Okay? The critical issue is what happens on the default case of no information. Andy > >
Received on Wednesday, 11 April 2012 13:55:46 UTC