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Re: [GRAPHS] g-box, g-snap, and g-text

From: Sandro Hawke <sandro@w3.org>
Date: Fri, 25 Feb 2011 14:11:51 -0500
To: nathan@webr3.org
Cc: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>, Ivan Herman <ivan@w3.org>, public-rdf-wg <public-rdf-wg@w3.org>
Message-ID: <1298661111.31192.2688.camel@waldron>
On Fri, 2011-02-25 at 18:19 +0000, Nathan wrote:
> Yup I agree, and also like the lexical/value space way of looking at 
> things as Antoine noted earlier.

Me, too.   This all sounds good.  

If we name the mapping between those two spaces with a URI, we've
addressed some of the Graph Literals use cases (except shared blank
nodes).

I'm pondering this blank nodes thread and wondering, yet again, if we
can just deprecate them.  :-)    [that's a joke, I think.]

Meanwhile, Nathan, you talked about capturing this terminology in the
wiki; maybe a page  called "Graph Terminology" with a comparison table,
with a column for the comparison feature, then a column for each of
g-box, g-snap, and g-text.   Then we have a row for each of the kinds of
distinctions we've talked about.    

Then, later in the page, we can talk about each of the related terms
(eg 'graph literal').   I'll try to take a pass at this later tonight if
you don't get to it first.

   - Sandro

> Pierre-Antoine Champin wrote:
> > On 02/25/2011 06:37 PM, Nathan wrote:
> >> Sandro / Ivan,
> >>
> >> AIUI, a g-box is a "box" which contains triples, the contents of the box
> >> can change over time, and the contents of the box at a particular point
> >> in time form a Set of Triples, a g-snap (a snapshot of the contents, the
> >> value of the box at time t, the state of the box at time t), g-snaps can
> >> be represented lexically in a data format so that they can be
> >> transferred over the wire, these serialized g-snaps are called g-texts.
> >>
> >> some clarifications to sandro's text following my understanding:
> >>
> >> Sandro Hawke wrote:
> >>> On Fri, 2011-02-25 at 17:30 +0100, Ivan Herman wrote:
> >>>> Another way of putting it is that a g-text is a special form of a
> >>>> g-box, which has the peculiarity of representing a g-snap in a text
> >>>> file.
> >>>
> >>> No, a g-text is not a special form of a g-box.  A g-text is a fixed
> >>> sequence of characters or bytes; a g-box is a potentially-mutable
> >>> collection.   If two g-texts are the same sequence, they are the same
> >>> g-text; that's not at all true of g-boxes.
> >>>
> >>> In a low-level language, like assembly or C, g-box would be some area of
> >>> memory, while a g-text would be some values that might be stored in that
> >>> memory.
> >>
> >> a g-box would be some area of memory, a g-snap would be the set of
> >> values stored in that memory at a point in time, and a g-text would be a
> >> serialization of that set of values.
> > 
> > According to Sandro's original definition [1], a g-snap is "an 
> > *idealized* snapshot of a g-box: it's a mathematical set (...)".
> > What is stored in memory is *not* a mathematical set, but a 
> > *representation* of the set, just as a serialization in a text file is a 
> > *representation*. Hence my proposal to unify both under the concept of 
> > g-text.
> > 
> > I like Antoine's proposal in [1] to consider g-snaps as elements of a 
> > value space, while g-texts would be elements of a lexical space (Antoine 
> > didn't use the g-* terminology, but I think I don't betray his thought).
> > 
> >>> Computer files are boxes, not texts, in this terminology -- they can
> >>> change, and they have an identity separate from their contents.
> >>
> >> Indeed, and g-texts have their own identity separate to both the
> >> contents of the box, and the box it self.
> > 
> > Agreed; but would you agree that a file foaf.rdf does not contain a 
> > graph; it contains a serialization. Similarly, an in-memory structure 
> > contains a sequence of bytes which are a *representation* of a graph, 
> > not the graph itself. The graph is unreachable.
> > 
> >> Relating to real life, let's say it's an apple box a-box:
> >>
> >> An a-box contains apples, the contents of the a-box at a particular
> >> point in time is an a-snap, a written list or photo of the contents at
> >> that point in time is an a-snap.
> > 
> > For the last occurence of "a-snap", you mean "a-text", of course :-D
> > 
> > It seems a bit farfetched to compare a "mathematical set" to a bunch of 
> > apples ;-D
> > 
> > Let me put it another way: if you buy a box containing '10 apples', you 
> > wouldn't mind if I ate one of the apples and replaced it with another 
> > one, as long as you still have the '10 apples' you paid for in your box. 
> > The a-set is the Idea of '10 apples'. The a-text are the 10 actual 
> > apples that happen to be in the box. The photo or written list does not 
> > count, as you can't eat them!
> > 
> >> Sorry to be a bit pedantic here, but I feel it's critical to keep clear
> >> distinctions between the three concepts
> > 
> > Sorry to be over-pendantic, but I agree with you that we need to have 
> > clear concepts :)
> > 
> >> box: a container
> >> snap: contents of the box at a point in time (or, the state of the box,
> >> or, the set of things in the box - set in the mathematical sense)
> >> text: a representation of a snap
> > 
> > again, if the snap is a mathematical object, you can not put it in a 
> > box. You can merely put an instance/token/representation of it in the box.
> > 
> >   pa
> > 
> > [1] http://lists.w3.org/Archives/Public/public-rdf-wg/2011Feb/0092.html
> > [2] http://lists.w3.org/Archives/Public/public-rdf-wg/2011Feb/0083.html
> > 
> >>
> >> Best,
> >>
> >> Nathan
> >>
> > 
> > 
> > 
> 
> 
Received on Friday, 25 February 2011 19:12:06 GMT

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