See also: IRC log
<trackbot> Date: 05 October 2011
<gavinc> trackbot, start meeting
<trackbot> Meeting: RDF Working Group Teleconference
<trackbot> Date: 05 October 2011
<scribe> scribe: yvesr
<davidwood> Scribe Yves Raimond
<davidwood> Scribe: Yves raimond
<davidwood> scribenick: yvesr
<iand> oops
<iand> mischat: one of us is p16, one is p17
<Guus> [partial regrets, have to leave after 30 min for the airport]
<iand> i was p17
davidwood: i'd like to go through
the scribe list
... adding new members on the scribe list
<mbrunati> today only via irc, phone problems
<AndyS1> +1
<Guus> +1
davidwood: minutes accepted
davidwood: liaise with html data
task force for turtle in html
... corresponding action closed
<gavinc> sadly did it twice thanks to gmail :(
davidwood: Guus had two action items
<Guus> we haven't done that yet, will talk to Fabien
davidwood: f2f either at MIT or BBC
<mischat> please update this page with your intentions http://www.w3.org/2011/rdf-wg/wiki/F2F2
<mischat> yvesr: the bbc are struggling to get the video conference system working, at a bare minimum we will have a webcam. everything is behind a proxy,
<mischat> davidwood: people should turn up a bit earlier at the bbc so that we can make sure that everyone gets online and set before the MIT lot turn up
<mischat> yvesr: people should email Yves if you want to hang out and have dinner after the days play
<davidwood> http://www.w3.org/2011/rdf-wg/wiki/Scribes
davidwood: who should we drop off the scribe list?
<mischat> nathan hasn't for a while
davidwood: any suggestions for people that have not shown up?
<mischat> axel ?
<gavinc> Nathan Rixham
ivan: Mohamed hasn't shown up, and Nathan
<mischat> how about Axel Polleres
<mischat> ?
ivan: Axel? Matteo?
... Jean-Francois?
<Scott_Bauer> I'm on the call as well
<NickH> thanks!
<ww> davidwood: i am not on the list! but happy to scribe after the F2F
ivan: heard back from our admin that the zakim channel is opened on both days
<ivan> code: 733294 ("RDF2WG")
sandro: the code will be rdf2wg
<sandro> for F2F
david: i will update the wiki page
<mbrunati> sorry for the last weeks, not enough time ( we are making a contest on open data ), F2F probably only remote for the BBC place, and december not able to scribe ( my marriage )
davidwood: we have two
proposals
... ... and we have a f2f next week
... ... we need to have a good plan by next week
<Guus> yes
<davidwood> http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs
davidwood: the graph task force page needs to be updated
<sandro> ACTION: richard to update http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs (but hopes others will help) [recorded in http://www.w3.org/2011/10/05-rdf-wg-minutes.html#action01]
cygri: i can do it, but it would be good if someone could contribute as well
<trackbot> Created ACTION-94 - Update http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs (but hopes others will help) [on Richard Cyganiak - due 2011-10-12].
davidwood: the two proposals come from sandro and cygri
<davidwood> http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs-UC
davidwood: the use-cases page
needs to be cleaned up
... sandro tried to get to the core of those use-cases in his
recent emails with the proveance xg
... it would be good to define test cases from these use
cases
... which would serve as a basis for evaluation
... it might be possible to collapse some use cases
together
ivan: we need to be looking at just 5 or 4 use cases, otherwise we'll be lost
davidwood: right now, we have 27
use cases
... ... most of those overlap
... ... it woul dbe better if we had 5!
cygri: agreed that 27 use cases
is too much, but it doesn't make sense to pick just one
... some of the use-cases come from practical use cases
<sandro> +1 the fish-restaurant use case should not be the only one. there are more immediate ones.
cygri: ... rather than just 'this is what we could do'
<sandro> http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs-UC
<sandro> cygri: 1.6, 1.1
cygri: particularly interesting
ones are, to me, 1.6 - versioning, 1.1 - overlap between
content of graphs,
... ... i'd like everyone in the group to do that on the
mailing list
<sandro> +1 please nominate your favorite use case.
davidwood: provencance use cases are important
<ww> i would argue that 6.2 bears on provenance
davidwood: ... that's why we are liaising with the provenance wg
<gavinc> I like 5.2
<gavinc> rather 5.2 is rather important to TopQuadrant
<sandro> WARNING -- NUMBERS MAY CHANGE. THESE NUMBERS REFER TO http://www.w3.org/2011/rdf-wg/wiki/index.php?title=TF-Graphs-UC&oldid=1473
<SteveH> 1.5 is important to us
<mischat> yvesr: has just added in a use-case given to him by Denny, about wiki based issues in the wikimedia project
yvesr: new use case from Denny, about Wikidata (Wikimedia project)
<Scott_Bauer> 4.8 has become obsolete and could be safely eliminated from the list if it overlaps with others
<Guus> I will provide example data (triples) about the Europeana Data Model use case, about metadata of heritage objects, including provenance data
davidwood: we need to evaluate proposals against test cases derived from use cases
<Guus> Target is by Friday
<Guus> [have to drop off]
davidwood: it needs to be done
before the F2F
... 48 hours
... would sandro and cygri be prepared to give an overview of
the respective proposals on named graphs? and how they relate
to UC?
sandro: i don't think i have a
proposal, exactly
... i might be able to give a list of questions or a summary
options
cygri: i can present my proposal
<Scott_Bauer> I should have referred to 4.7, "Applying Named Graphs to a Terminology Server" based on the alternate url above.
<sandro> ACTION: sandro to present after Richard, F2F2 day 1, about where we might need more than his proposal gives us. [recorded in http://www.w3.org/2011/10/05-rdf-wg-minutes.html#action02]
<trackbot> Created ACTION-95 - Present after Richard, F2F2 day 1, about where we might need more than his proposal gives us. [on Sandro Hawke - due 2011-10-12].
davidwood: focus at the F2F on use-cases, and turn them into test cases
<scribe> ACTION: cygri to present his proposal for named graphs at the F2F [recorded in http://www.w3.org/2011/10/05-rdf-wg-minutes.html#action03]
<trackbot> Created ACTION-96 - Present his proposal for named graphs at the F2F [on Richard Cyganiak - due 2011-10-12].
cygri: i am strugginlg to find the UC that motivates the argument made by PatH and Pierre-Antoine
pchampin: i can't speak for PatH,
but maybe i can work on a negative example where i show the
freedom given by cygri's proposal could be harmful
... a lot of use cases are arguing that an IRI in a graph can
be used to access a graph in a dataset
... cygri call that a social convention
... i think it has surprising consequences
<sandro> hard to hear davidwood
<sandro> better
<cygri> pchampin, if you could write up that use case (negative or not), that would be much appreciated
<pchampin> @cygri I will
davidwood: ability to access a
graph by an IRI seems like a non-issue
... struggling to understand the counter-argument
<pfps> what happens when there is a mismatch between a quad and actuality?
<sandro> the same thing as happens any other time there is bad data, pfps, I think....
<pfps> but if quads carry actuality then having them wrong is like having 7 be 8!
<davidwood> cygri, can you please scribe your comments into IRC?
pfps: there is an issue having the semantics of rdf pushing into the semantics of quads
davidwood: isn't the point of rdf
that anybody can say anything about anything?
... if i choose to say that 7 is 8, it's fine
pfps: it's different than rdf
saying that 7 is 8
... we don't have a proposal for how the semantics would
work
... they can be right, but not very useful
<sandro> thus the drive to make sure our usecases are ... useful. :-)
<cygri> cygri: i think we agree that in implementations, IRIs can be used to access graphs. the disagreement is about how graph names should be treated in the formal semantics. minimalist position: the semantics should be concerned with single graphs only. alternative position: the semantics should make graph IRIs denote the graphs
pfps: the semantics should be
concerned with single graphs only
... right now, they do
davidwood: should the rdf semantics ignore named graphs?
pfps: you could push those notions in the rdf semantics, but it might not be helpful
davidwood: if you have a syntax that allows for named graphs, would you efectively just add a triple?
<ww> statement identifiers...
davidwood: does it *need* to impact the semantics?
pfps: leaving named graphs out of semantics loses something, but it might be more trouble than it's worth
gavinc: i thought everybody agreed that reification is broken, in rdf
<pfps> RDF reification is more trouble (>0) than it is worth (<=0)
davidwood: but could it help us
out of the named graphs problem?
... a bounded type of reification, specific to named graphs
<Andy> Are we agreed how reification is broken? (and I think it is broken)
SteveH: some of the proposals seem to be trying to rule out certain things that people are currently doing
<gavinc> +1
<sandro> SteveH: some of the proposals seem to be trying to rule out things some people are doing in SPARQL.
SteveH: we shouldn't do that - we
should support creating some structure around what people are
doing right now
... we don't want to be enormously disruptive
davidwood: you overestimate our impact on the market
<cygri> SteveH++
SteveH: but we should try not to get ignored
<pchampin> @SteveH: the graph IRI as defined by the RDF spec does not have to be the graph IRI as used by SPARQL
sandro: i can name one of these proposals
<pchampin> though we should be careful to name it differently, of course
sandro: using graph tags to specify the subject of the doc
<LeeF> I think that that's a pretty common practice, isn't it?
<gavinc> Yes, TopQuadrant is aware that we shouldn't be doing that ;)
SteveH: other examples would be mandating that a graph URI must be dereferencable
<LeeF> I'm pretty sure dbpedia's SPARQL end point names graphs with the subject of the graph (at least, it did at some point)
<LeeF> Anzo does it as well, in some modes
sandro: we shouldn't impact on anybody's code
<gavinc> O'Reilly Media's does too
<cygri> LeeF, the one at dbpedia.org/sparlq doesn't. the DBPedia Live one might do it
sandro: i think it is bad
practice to use the subject as the base id of the graph
... maybe we can reach a proposal that is actually helpful,
motivating people to switch
davidwood: like RDFa 1.1
<gavinc> Btw, the confusion here is rather bad. TopQurant software uses the same "method", everything tends to ask about Base URI
SteveH: we should look at the linked data work, with no strict conventions about how to name graph
davidwood: if you're right, then we don't need standards
<LeeF> cygri, my experience might have been a long time ago, as well.
SteveH: we still should recommend what to do
<gavinc> Where base URI == OWL Ontology == Base URI 3986 == Graph Name :\
<sandro> That wasn't me!
<LeeF> cygri, also the chance that i'm hopelessly confused :)
<Andy> +1 to advice and suggestions and "good practice" docs
<ww> MAY/SHOULD vs MUST?
<NickH> SteveH++
<gavinc> +1 to andy on advice and good (not best) practices
sandro: responding to what pfps said - i don't have a particular position - but intution is that we need more than we have now
<pfps> it appears that we need use cases and worked out solutions to see what machinery is needed
<sandro> yeah. :-(
<sandro> (frown because it's hard work.)
<cygri> pfps++
<davidwood> That's why we need to move toward test cases
cygri: how to map terminology to
use-cases? (e.g. subgraphs)
... ... in that document ivan wrote about graphs
ivan: that document talked about
graph literals, where you hit the issue of sub-graphs
etc.
... those propoerties were mainly coming from that
... if we don't have graph literals at all, the problem becomes
very different
<Souri> Why don't we just present graphs as a way of scoping (using a IRI tags) for RDF's uniqueness requirement? How people use graphs is their business.
pchampin: graph literals may be very important
ivan: i didn't say they weren't
<sandro> ivan: if we have graph literals then those additional properties are important
<sandro> pchampin: If we don't give special semantics to graph IRIs, then we'll need more ways to talk about graphs.
pchampin: if we refuse to give special semantics to graph IRIs, my intuition is that it would become more important - we need to know how to treat a graph IRI
<pchampin> pchampin: ... that we can express in RDF what is the relation btw a graph and its IRI in a give dataset
<pfps> what kind of special semantics?
davidwood: strawman proposal about RDF datasets
<davidwood> Strawman proposal Richard: http://dvcs.w3.org/hg/rdf/raw-file/default/rdf-concepts/index.html#section-multigraph
<pchampin> @pfps: that the graph IRI actually denotes the g-snap, for example
sandro: i thought we were going through the issues list?
davidwood: this specific issue is
abstract syntax to talk about multiple graphs
... i will go through the issues list, preparing for the
F2F
cygri: the strawman proposal is more or less a copy of the SPARQL 1.1 spec, expect it avoids saying that the graph name is an identifier for the graph
<ww> [I have to drop off the call, apologies]
cygri: it motivates the need for
syntaxes, to write those different graphs
... it's important to have a strawman there
<pfps> Looks benign to me, and useful to pull into RDF Concepts.
<Andy> and RDF-WG is doing syntax for something like this.
davidwood: does it look benign to everyone?
sandro: i don't understand why the default graph doesn't have a name
davidwood: should it not have necessarily a name?
<pfps> the sentence *could* just be removed.
pfps: thereis nothing really
wrong with that, the sentence could be removed
... that sentence could be somewhere else?
<pchampin> proposal: the default graph has no name, but could be identical to a named graph
MacTed: if you use a default graph, it is not named
<Andy> "There is no name for the default graph role."
MacTed: if it is, then you use a named graph
<pfps> the sentence about the default graph not having a name could just be removed, without affecting the meaning of the section
<pchampin> @sandro: I think we mean g-snaps here
<pfps> "There is no name for the default graph."
sandro: a dataset is entirely g-snap
<Andy> sandro - That is true in SPARQL - its immutable (a graph store is mutable)
<sandro> +1 to removing "The default graph does not have a name."
cygri: it might be a good idea to
remove the sentence if it brings confusion - it is
redundant
... +1 to sandro, datasets are only composed of g-snaps
... what we have here is essentially a 'dataset snap'
<gavinc> -0.5 to removing "The default graph does not have a name"
cygri: it is just a snapshot
<gavinc> EXACTLY one.
<pfps> around here it was snapping trees - courtesy of tropical storm Irene :-)
sandro: if you think of that in
terms of syntax, it makes it very clear that th edefalut graph
doesn't have a name
... why do you need to do that to name the triples that are
already in the default graph?
<gavinc> TriG does NOT have triples without {}
<sandro> david: Why do you have the move the triples into curly braces to give them a name?
MacTed: either they exist in a named graph, either they don't
<gavinc> the {}s may not have a graph_name as it's optional
<sandro> sorry, Gavin, call it DTriG or something.
<gavinc> sandro, np. But people have claimed that TriG is better for not having anything outside of {}s ;)
MacTed: default graph is a g-box, it can't be a g-snap
<Andy> The default graph is a set - it can not change. It is a g-snap. a dataset is a "set"
<sandro> (right, I think Ted is wrong about dataset/gbox)
Andy, +1
sandro: the default graph is not
a g-box
... in practice, you can treat it as mutable, but in theory it
is immutable
<LeeF> I don't agree with sandro on everything, but definitely agree with him on this :)
<gavinc> Yeah
<cygri> “RDF graph” as per RDF Concepts = g-snap
davidwood: in rdf concepts, every time we say the word graph, we mean g-snap
cygri: agreed
... defined as a set of triples, in the mathematical
sense
... when you add a triple, you get a different graph
davidwood: if you change a graph in a dataset, then you change the dataset
<gavinc> Why not Graph Store?
sandro: maybe we could consider a container of immutable graphs?
<Andy> PUT http://example/gbox
sandro: a 'graph dispenser'
<Souri> I am happy :-) with just presenting graphs as a way of scoping (using a IRI tags) for RDF's uniqueness requirement. I think how people use graphs is their business.
<LeeF> As gavinc says, SPARQL 1.1 calls the container a "graph store"
<LeeF> (SPARQL 1.1 Update, specifically)
<Andy> +1
<gavinc> as does SPARQL 1.1 Graph Store HTTP Protocol
<LeeF> aye
<sandro> @souri have you looked at the Graphs use cases? Do you know how to address them (without this stuff)?
bye!
<mbrunati> bye
This is scribe.perl Revision: 1.136 of Date: 2011/05/12 12:01:43 Check for newer version at http://dev.w3.org/cvsweb/~checkout~/2002/scribe/ Guessing input format: RRSAgent_Text_Format (score 1.00) Succeeded: s/lisiase/liaise/ Succeeded: s/sandro:/david:/ Succeeded: s/forcepage/force page/ Succeeded: s/1.2/1.1/ Succeeded: s/:// Succeeded: s/xg/wg/ Succeeded: s/provencance/provenance/ Succeeded: s/triple/a triple/ Succeeded: s/looses/loses/ Succeeded: s/sandro/SteveH/ Succeeded: s/LeeF:/LeeF,/ Succeeded: s/davidwood/sandro/ Succeeded: s/>/?/ Found Scribe: yvesr Found Scribe: Yves raimond Found ScribeNick: yvesr Scribes: yvesr, Yves raimond WARNING: No "Present: ... " found! Possibly Present: AZ AlexHall Andy AndyS AndyS1 Arnaud Arnaud1 David_Wood Guus Ivan LeeF MacTed NickH OpenLink_Software P13 P14 P15 P16 P17 P18 P2 P26 P30 P4 P54 P7 Peter_Patel-Schneider Scott_Bauer Souri SteveH aaaa aabb aacc aadd code cygri cygri_ david davidwood ericP gavinc iand manu manu1 mbrunati mischat moustaki nunolopes pchampin pfps proposal sandro scribenick swh trackbot ww yvesr You can indicate people for the Present list like this: <dbooth> Present: dbooth jonathan mary <dbooth> Present+ amy Found Date: 05 Oct 2011 Guessing minutes URL: http://www.w3.org/2011/10/05-rdf-wg-minutes.html People with action items: cygri richard sandro WARNING: Input appears to use implicit continuation lines. You may need the "-implicitContinuations" option.[End of scribe.perl diagnostic output]