- From: pat hayes <phayes@ai.uwf.edu>
- Date: Fri, 31 Aug 2001 12:23:12 -0700
- To: Stefan Kokkelink <skokkeli@mathematik.uni-osnabrueck.de>
- Cc: www-rdf-logic@w3.org
>pat hayes wrote: > > ... > > >Why did you decide to define it for RDF graphs? > > > > ... > > RDF graphs and Ntriple documents are in 1:1 correspondence, modulo > > re-ordering of lines and renamings of anonymous node labels, so it is > > relatively trivial to map between them in any case; and it is also > > easy to map directly between graphs and (existential-conjunction) > > expressions in a linear logical notation, should you wish to do so. > > In fact, if one is willing to put up with the awkwardness of somehow > > distinguishing between 'free' and 'bound' anonymous nodes, the model > > theory could be applied directly to the n-triples syntax. > >Although I completely agree on this (and on the decisions >made by RDFCore regarding anonymous nodes and RDF graphs ) >it should be noted that there is no 1:1 correspondence between >XML serializations and RDF graphs (and hence Ntriple also). But it is onto, ie every XML serialization maps to a unique graph, right? (If not, please give an example.) So if the semantics assigns a meaning to every graph, then it also does to every XML serialization, which is all that it needs to do in order to provide a semantics for the serialization language. >I think there are two possible views on this. > >1. Accept that not all RDF graphs have a XML serialization. That would be my own preference. Is there a problem with this? >2. Define an RDF graph to be a 'valid' RDF graph if there > exist a XML serialization. Well, I'd prefer a different word, call it 'XML-compliant' or some such. But this is a different issue, to do with the acceptability of RDF graphs to some processor. The model theory only has to provide an unambiguous interpretation for every expression; if it also provides one for some other expressions that is harmless. Pat Hayes --------------------------------------------------------------------- (650)859 6569 w (650)494 3973 h (until September) phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Friday, 31 August 2001 15:22:03 UTC