Re: First order logic and SPARQL

Hi Pat,

On Sun, Sep 5, 2010 at 6:31 PM, Pat Hayes <phayes@ihmc.us> wrote:

On Sep 5, 2010, at 4:48 PM, Bob MacGregor wrote:

> My personal interest is in a query language for RDF that's easy to use,
and, among other things,
> has a negation operator that is intuitive.

Id be interested to know what you consider to be intuitive here. Is negation
by failure intuitive for most Web sources? Do you routinely conclude, from a
failure to find a sentence asserted on a website, that it is false?

Fundamental to your argument seems to be "sentence asserted on a website".
If I grabbed
triples from some random Website, I might not be confident in using NAF.
But I don't do that.  I work
with graphs that I've built from sources I trust, and I know which parts of
the graph are expected to
be complete, and NAF is perfect for those parts.

- Bob