[Versa] Question about query

[Chimezie Ogbuji]

> all() -> dc:creator -> eq(<mailto:foo at yahoo.com>)
> 
> It's possible when the query is formulated that <mailto:foo at yahoo.com>
> is not in the graph.  According to this magic implication we're talking
> about, this should instantly become the empty set.  Or are we saying
> that we would *mandate* lazy determination of the value of that item?

See, I would think the way I would think about it for this query would
be to filter the dc:creator values by string comparison to the
resource name:

all() - dc:creator -> eq('<mailto:foo at yahoo.com>')    
or
[- dc:creator -> eq('<mailto:foo at yahoo.com>')]

In which case, once again literals are actual values in the query
space but 'resources' are matched by a uri pattern (explicit or
qname).  The only confusion, perhaps, is the sticking point that
literals are now resources in the model (when I say 'resource' i mean
it in the old sense).

> all() -> dc:creator -> neq(<mailto:foo at yahoo.com>)

all() - dc:creator -> neq('<mailto:foo at yahoo.com>')

I wouldn't think you would want to interpret the use of neq (or eq)
here to mean logical identity.  In which case you would have to
account for 'smushing' the graph by collapsing blank nodes that
identified the same resource via DL inferencing that produces
owl:sameAs statements (consider that you mean foaf:mailbox instead of
dc:creator, which is an inverse functional property that could be used
to calculate logical identify explicitely).  This is much more
complicated than comparing the string representation of a uri
reference against another string.

I guess my question is given how RDF has now changed, with regard to
literals and resources both being in the same class, will it ever be
reasonable to expect to be able to compare resources and literal not
by the string representation of their URI but by logical identify
(log:equalTo and owl:sameAs)?


Maybe I should pick the brains of some folx in #swig