Re: Layers

On Mon, Apr 30, 2012 at 10:01:23PM +0200, Dan Brickley wrote:
> > A surface is something like a bundle of overlaid layers, like a movie still
> > made up from overlaid cels. Or, put the other way, a layer is part of a
> > suface which has been peeled off and raised above the surface. (Danbri's
> > pictures work either way.) Think of the surface as the opaque background of
> > the transparent layers: bnodes are marks on this surface. We could copy a
> > layer onto another surface, for example, and then the suface idea of
> > conjunction (replacing unions and merges) works here also: to conjoin A and
> > B, just copy them both onto a new surface.
> That's quite interesting. It's refreshing to be able to start to articulate
> operations that work with larger units than triples. I wonder what other
> kinds of operations between graphs/layers/surfaces are useful in everyday rdf
> (/owl) life?

The Layers metaphor fits very nicely with the notion of Levels in the FRBR use
case as described at [1]:

    This proposal views descriptions of WEMI entities as bundles of statements
    made at different levels of abstraction, from the most concrete Item level
    to the most abstract Work level.  Multi-level WEMI descriptions specify the
    characteristics that any given Item shares with other Items at the level of
    Work, Expression, and Manifestation.  Ideally, it would be possible to
    incorporate descriptions of resources at the Work, Expression, and
    Manifestation levels, maintained in a distributed manner by various
    institutions, into the local descriptions of particular Items.  

(In our discussion a few weeks ago, David wondered whether the inferencing
requirement expressed therein suggests the need for a graph that holds named
graphs (nesting) [2].  I'm wondering whether the Layers idea re-frames that 



Tom Baker <>

Received on Monday, 30 April 2012 22:00:38 UTC