RE: Blank nodes must DIE! [ was Re: Blank nodes semantics - existential variables?]

Yeah, the atomicity of the chunk is the point. This even applies to quantities. 25.4mm is identical to 1” – they are the same thing. Any engine that operates with quantities needs to understand that. ’25.4’ and ‘mm’ cannot be separated. Coordinates are slightly more complex but it comes down to the same thing. A single element within a set of coordinates that describes a position in space is not independent of the other numbers in the tuple, or of the coordinate reference system within which they are expressed. One value should never be used independent of the others. Exactly the same position on the earth will be denoted by three different numbers if embedded in a different coordinate reference system. You can only ‘reason’ over them as a group, not individually.


From: Dan Brickley <danbri@danbri.org>
Sent: Thursday, 16 July, 2020 23:58
To: Jeen Broekstra <jeen@fastmail.com>
Cc: Semantic Web <semantic-web@w3.org>
Subject: Re: Blank nodes must DIE! [ was Re: Blank nodes semantics - existential variables?]

…

I believe the big appeal of putting it all into the zone we call "literals" is that you get a kind of atomicity; that chunk of data is either there, or not there; it is asserted, or not asserted. With a triples-based (description of a ) data structure you have to be constantly on your guard that every subset of the full graph pattern is at least sensible and harmless, even when subsetting these chunks is often confusing or misleading for data consumers. I can't help wondering whether notions of graph shapes from shacl, shex (and sparql) could be exploited to create an RDF-based data format which had atomicity at the level of entire shapes.

Dan




Jeen