- From: Pat Hayes <phayes@ihmc.us>
- Date: Tue, 1 Mar 2011 10:09:43 -0600
- To: Ivan Shmakov <oneingray@gmail.com>, Ivan Shmakov <ivan@main.uusia.org>
- Cc: semantic-web@w3.org
On Mar 1, 2011, at 8:25 AM, Ivan Shmakov wrote: > Let us consider the following serialization / deserialization > scenario. > > First of all, there's a graph that has a blank node, _:blank. > > Now, two subgraphs of the graph are serialized, both referencing > _:blank. > > Do I understand it correctly that (in the absence of reasoning) > deserializing both of the subgraphs back into an RDF store will > necessarily lead to the creation of /two/ blank nodes (where > there once was one)? Yes. Unless, that is, the deserializing process is somehow able to know that these are two serializations of the same single original graph. But before you label this an "issue", let me turn the scenario around. Suppose there are two graph documents which were composed independently but happen to be isomorphic as graphs, and each contains a blank node. They might for example be parts of larger graphs which describe groups of people, and each might say that someone exists who is Chinese and owns a red Honda. Now serialize these "identical" graphs into two identical serializations and send them to a common source and ask it to deserialize them into a single graph. Should it merge these blank nodes into one? It may well be that if more information had been sent, it would have been clear that these were two different people. But even if not, it is clear that can be no general warrant to presume that two different blank nodes must co-refer, unless of course one knows that the provenance of the information guarantees that they do. > > PS. … Or should it be called a “Humpty Dumpty issue”? I suggest it is more like assembling pots from broken shards found by archeologists. One needs more knowledge to be sure that pieces that seem to fit together to in fact do so. Pat Hayes > > -- > FSF associate member #7257 ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Tuesday, 1 March 2011 16:10:48 UTC