On Mon, Oct 4, 2010 at 1:03 AM, Sampo Syreeni <decoy@iki.fi> wrote:
> ....
> To give you an example, how about Person-type bnodes, which have exactly
> the same names, relatives, cars, addresses and birthdates as me, yet whose
> cars happen to have different colors from mine? In the simplest
> counter-example of this sort, all of the subjects would be bnodes, not one
> of which has an unambiguously distinguishing attribute by itself within its
> type. In general only the network connectivity of a node distinguishes it
> from any other. In this case, are two bnodes with my name and other directly
> shared non-bnode attributes the same or different, if the transitive
> attributes differ?
the two persons have a different car, so none of the bnodes can be
"leanified" away
> How about when the transitive closure from me agrees with a traversal
> starting from some other node in all non-blank nodes, globally?
>
it doesn't matter where you start traversal.
>
> In the relational framework the answer is, ideally graph isomorphism should
> dictate full equivalence.
graph isomorphism dictates full equivalence, but graphs expressing the same
content (by RDF semantics) need not be isomorphic, unless they are both
lean.
Cheers,
reto