14:06:31 <RRSAgent> RRSAgent has joined #rdf-star
14:06:36 <RRSAgent> logging to https://www.w3.org/2024/04/12-rdf-star-irc
14:06:41 <Zakim> Zakim has joined #rdf-star
14:07:03 <TallTed> TallTed has changed the topic to: RDF-star WG - Semantics Task Force - 2024-04-12 agenda: https://www.w3.org/events/meetings/6d0cd306-0be8-4267-865a-6272cc8d9da4/20240412T100000/
14:07:41 <TallTed> meeting: RDF-star Semantics TF
14:07:43 <TallTed> agenda: https://www.w3.org/events/meetings/6d0cd306-0be8-4267-865a-6272cc8d9da4/20240412T100000/
14:07:44 <agendabot> TallTed, sorry, I did not recognize any agenda in https://www.w3.org/events/meetings/6d0cd306-0be8-4267-865a-6272cc8d9da4/20240412T100000/
14:07:45 <TallTed> scribe: ?scribe?
14:07:47 <TallTed> chair: ?chair?
14:07:49 <TallTed> present+ souri, gkellogg, niklasl, TallTed, tl, AndyS, enrico, fsasaki
14:07:51 <TallTed> topic: continuing discussion on how to constructively blend Amazon's concerns into the current structure of the RDF 1.2 proposal
14:09:19 <TallTed> subtopic: many-to-many vs many-to-one reifiers-to-triple_terms
14:11:47 <TallTed> RRSAgent, draft minutes
14:11:49 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
14:12:14 <enrico> enrico has joined #rdf-star
14:12:18 <enrico> present+
14:12:19 <TallTed> previous meeting: https://www.w3.org/2024/04/11-rdf-star-minutes.html
14:12:19 <TallTed> next meeting: https://www.w3.org/2024/04/18-rdf-star-minutes.html
14:12:24 <TallTed> RRSAgent, draft minutes
14:12:26 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
14:12:34 <TallTed> RRSAgent, make logs public
14:13:07 <Souri> Souri has joined #rdf-star
14:13:16 <enrico> q+
14:13:16 <TallTed> regrets+ ora
14:13:16 <Souri> present+
14:15:24 <Souri> q+
14:16:17 <pchampin> q+
14:16:29 <enrico> ack enrico
14:16:34 <enrico> ack souri
14:18:48 <enrico> enrico: a solution is to have general well-formedness for many-to-many, and then various best practices: for LPGs, annotations, provenance, n-ary relations, events and situations, etc
14:19:20 <TallTed> RRSAgent, draft minutes
14:19:21 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
14:19:42 <AndyS> souri: suggests an "LPG profile"
14:20:17 <AndyS> souri: (full) RDF 1.2 should be limited by LPG
14:20:27 <AndyS> scribe: AndyS
14:20:29 <TallTed> s/?scribe?/ad-hoc/
14:20:29 <TallTed> scribe+ enrico, AndyS
14:20:35 <fsasaki> q+
14:20:50 <TallTed> RRSAgent, draft minutes
14:20:51 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
14:21:02 <AndyS> souri: not everyone is interested in that restriction.
14:21:13 <enrico> ack pchampin
14:21:28 <tl> I understood that souri: (full) RDF 1.2 should NOT be limited by LPG
14:21:48 <AndyS> pchampin: about undirected edges and the need for many-to-many
14:21:51 <TallTed> s/scribe: ad-hoc//
14:21:51 <TallTed> RRSAgent, draft minutes
14:21:52 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
14:22:24 <AndyS> ... there are other ways to model this e.g. subproperty, symmetric properties
14:22:51 <enrico> enrico: LPG undirected edges need many-to-many: << :w1 | :liz :married :richard >> :location :las-vegas . << :w1 | :richard :married :liz >> :date 1966 .
14:23:05 <AndyS> s/souri: (full) RDF 1.2 should be limited by LPG/souri: (full) RDF 1.2 should not be limited by LPG/
14:23:18 <niklasl> q+
14:24:22 <TallTed> RRSAgent, draft minutes
14:24:23 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
14:24:44 <AndyS> q?
14:24:57 <enrico> ack fsasaki
14:24:58 <AndyS> ack fsasaki
14:25:26 <TallTed> s/?chair?/ad-hoc/
14:25:34 <AndyS> fsasaki: best practice for LPG encoding to give best interoperability - not part of SemTF
14:25:35 <tl> q+
14:25:50 <AndyS> ... maybe main meeting and with LPG people
14:26:43 <AndyS> niklasl?
14:28:12 <AndyS> niklasl: my angle is to understand the problem with many-to-many (M2M) from an LPG POV.
14:29:02 <AndyS> ... if an edge in LPG is an instance of a relationship, (unclear to me) - no notion of denotes.
14:29:56 <AndyS> ... are we going overboard here? Entailment forces M2M
14:32:07 <AndyS> ... does M2M to confuse more than it helps? I don't think so.
14:33:23 <AndyS> tl: sematics of multi-edge reification - is a foreach semantics or it applies to the collection.
14:34:22 <pchampin> q+
14:34:57 <niklasl> q-
14:35:15 <AndyS> ack tl
14:35:43 <Souri> Here is a source of confusion for me: I think rdf:reifies is multi-valued, but not set-valued. This is different than a named graph, which is an association of a resource with a set of triples.
14:36:22 <TallTed> RRSAgent, draft minutes
14:36:23 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
14:36:29 <Souri> q+
14:37:56 <fsasaki> q+
14:38:22 <AndyS> enrico: what is confusing here if others can use one reifier for multiple triples
14:38:44 <AndyS> ack pchampin
14:38:52 <AndyS> pchampin: I am neutral here.
14:39:44 <AndyS> ... I think that the confusing is how to explain (not the semantics) the rationale for the design - the intended meaning
14:39:52 <enrico> q+
14:40:12 <AndyS> ... e:g: rdf:subject is different to rdf:object
14:40:39 <AndyS> ... not clear we have the same understanding of rdf:refiies
14:41:40 <TallTed> s/refiies/reifies/
14:41:45 <AndyS> ... "intended meaning" is not captured by formal semantics
14:42:17 <AndyS> ... rdf:reifies -- what is the "intended meaning"?
14:42:51 <AndyS> ... don't know what the graphic is for the multi-triple case.
14:43:31 <pfps> pfps has joined #rdf-star
14:43:36 <enrico> ack souri
14:43:44 <pfps> q+
14:43:44 <pfps> present+
14:43:54 <fsasaki> present+
14:44:28 <AndyS> souri: hard to cast LPG in RDF language
14:45:54 <AndyS> ... I'm asking about multi valued rdf:reifies - multi-valued or container valued?
14:46:01 <tl> q?
14:46:45 <pfps> q+, to say that if there is no many-to-many reification then the many-to-many case looks exactly like the many-to-one case as far as users are concerned
14:47:49 <AndyS> s/container valued/container-valued/
14:47:58 <tl> if a person has hobbies tennis,swimming and skiing, those are three distinct hobbies, but they are also all all sports related hobbies. the distinction between multi-value and set doesn't make much sense to me. it depends on teh contents
14:49:35 <AndyS> ask fsasaki
14:49:41 <fsasaki> Citation from Rinke Hoeskstra, Elsevier, from LinkedIn: "Compatibility is essential, not just for querying across the graphs, but also for graph production pipelines where the wrangling of data happens in RDF and the serving happens in a PG projection. "
14:49:43 <AndyS> ack fsasaki
14:49:52 <AndyS> s/ask fsasaki//
14:51:51 <AndyS> ack enrico
14:52:19 <AndyS> enrico: the meaning of rdf:reifies will be in the best practices document.
14:53:00 <AndyS> ... let's wait for this document
14:53:17 <pchampin> q+
14:53:31 <AndyS> ... several profiles for LPGs which will take sometime to develop
14:54:59 <AndyS> ack pfps
14:56:13 <AndyS> pfps: re: the neptune input. many-to-many looks like many-to-one - SPARQL Update is affected, nothing else.
14:56:15 <AndyS> q+
14:56:33 <AndyS> ... not seeing users are hurt by M2M.
14:57:12 <AndyS> ack pchampin
14:57:17 <pfps> or even affected by many-to-many
14:57:54 <AndyS> pchampin: M2M needs to represent the reification
15:00:46 <AndyS> ... "reificiation" is an abstract concept making it hard to understand and M2M adds to that
15:01:13 <pchampin> q?
15:01:23 <pchampin> scribe+
15:01:51 <pchampin> AndyS: to pfps's remark that M2M looks like M2O, it is not as simple with SPARQL;
15:02:02 <pchampin> ... querying means closing the world.
15:02:13 <pchampin> q?
15:02:18 <pchampin> ack AndyS
15:02:20 <AndyS> ack AndyS
15:03:19 <Souri> q+
15:03:34 <pchampin> niklasl: I expect the interpretation of an edge in LDP to be the relationship.
15:03:40 <AndyS> niklasl: re: users of LPG -- the interpretation of the edge as nodes and edges.
15:03:47 <pchampin> scribe-
15:04:09 <pchampin> q+
15:06:41 <gkellogg> scribe+
15:07:12 <AndyS> scribe-
15:07:13 <pchampin> ack Souri
15:07:40 <gkellogg> Souri: is rdf:reifies multi-valued, or not.
15:07:43 <tl> q+
15:07:59 <gkellogg> ... Is is multi-valued or set-valued?
15:08:41 <gkellogg> ... If you have the same reifier for multiple triples, we may want to add something that affects multiple triples.
15:09:12 <gkellogg> ... Once you've done that, you can't say thing about an individual triple now; you'd need to create a new reifier to connect only to one triple to say things about that.
15:09:58 <gkellogg> ... The ability to have multi-valued rdf:reifies gives the user to say things about multiple triple terms together with one annotation or set of annotations, while staying inside a single RDF named graph.
15:10:27 <gkellogg> ... That ability is not there today; you can create multiple graphs, but they're in different scopes; you're not able to take sub-groups of triples and annotate them.
15:10:40 <TallTed> RRSAgent, draft minutes
15:10:41 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
15:10:52 <gkellogg> ... The ability to allow multi-valued rdf:reifies provides for different modeling opportunities.
15:11:08 <pchampin> q?
15:11:12 <pchampin> ack pchampin
15:11:36 <gkellogg> pchampin: Responding to Souri, your question about set- vs multi-valued is important.
15:11:38 <TallTed> i/regrets+ ora/present+ pchampin
15:11:49 <gkellogg> ... My position is that the open world assumption, it's clearly multi-valued.
15:12:26 <gkellogg> ... If the meaning is that it can reify multiple triples, then there could be other triples being reified I'm not aware of.
15:12:53 <gkellogg> ... If it's a set of triples, the set cannot be known, because some rdf:reifies statements may exist that I'm not aware of.
15:13:01 <Souri> q+
15:13:05 <gkellogg> ... A set is open ended (multi-valued).
15:13:17 <gkellogg> ... That makes many-to-many confusing.
15:13:56 <gkellogg> ... As for LPG edges, they don't have a formal definition so you can't talk about denotation.
15:14:28 <gkellogg> ... That was my argument about not having a single predicate for expressing reification, and types could have some advantages.
15:14:44 <gkellogg> ... That is what makes mapping fron RDF to LPG difficult.
15:14:53 <niklasl> +1 to that
15:14:55 <pchampin> q?
15:14:58 <gkellogg> ... We should keep rdf:reifies high-level and under-specified.
15:14:59 <pchampin> ack tl
15:15:06 <gkellogg> tl: +1 to that.
15:15:32 <gkellogg> ... Does Souri mean forEach semantics for multi-valued?
15:16:08 <gkellogg> Souri: If you say jon plays sport cricket and footbal, it can be multi-valued.
15:16:42 <gkellogg> tl: By forEach, I mean if you can use it to say that an annotation applies to each such triple, or the set of those triples.
15:16:46 <pchampin> q+
15:17:21 <gkellogg> ... You might give a date and want it to apply to each edge individually.
15:17:42 <gkellogg> ... There is a continuum between the two extremes.
15:18:23 <gkellogg> ... In general, I think we can leave it open. If you come from LPG you probably think it's for each edge.
15:18:50 <gkellogg> ... forEach was part of RDF in 1999, but didn't make it into 1.0.
15:19:00 <gkellogg> ... That suggests it's not actually a problem.
15:19:03 <TallTed> RRSAgent, draft minutes
15:19:04 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
15:19:13 <pchampin> q?
15:19:20 <pchampin> ack Souri
15:19:46 <gkellogg> Souri: We have things that are sets of triples, but not sets of triple terms.
15:20:08 <gkellogg> ... The connection between a reifier connects to individual triple terms, not a set of triple terms.
15:20:22 <TallTed> s/jon plays sport cricket and footbal/jon playsSport cricket and jon playsSport football/
15:20:27 <gkellogg> ... A set of triples does not really exist.
15:20:52 <gkellogg> ... We could have a set of triple terms sharing a single reifier.
15:22:02 <gkellogg> ... Suppose I say that sports cannot be put in a set, you can't talk about cricket, soccer, etc.
15:22:15 <gkellogg> ... But, in RDF, a set of triples is fundamental, as it defines a graph.
15:22:29 <gkellogg> ... But, triple terms are different than triples.
15:22:57 <gkellogg> ... If it's multi-valued, it cannot connect to a set of triples, which is what would be normal in RDF.
15:23:25 <gkellogg> ... We need to show a need for both views.
15:23:33 <pchampin> q?
15:23:59 <gkellogg> tl: The reason triple term is abstract, and occurrences are different topics.
15:24:32 <gkellogg> Souri: In RDF we don't use a set of URIs. Can we talk about a set of URIs.
15:25:17 <gkellogg> ... We can talk about how to express a Bag, but a Graph is a set of triples. We don't talk about a set of triple terms.
15:25:50 <gkellogg> tl: We say John has several hobbies and we can talk about the set of those hobbies.
15:26:34 <gkellogg> pchampin: gkellogg pointed out the Bag collection in RDF 1.0, as those have an open-world assumption.
15:26:40 <AndyS> q+
15:27:10 <gkellogg> ... The problem is, because of OWA, you can never know it's complete. That's why lists were created, as they're closed.
15:27:34 <gkellogg> ... If a list has been tampered with, you can tell.
15:28:01 <gkellogg> ... Seq was similar, but not closed.
15:28:38 <gkellogg> ... Also, lists have an order; if I had to describe a set, I probably would use a list, but say that order was insignificant.
15:29:05 <pchampin> :graph :hasTriples (<< s p o >> <<s' p' o' >>).
15:29:20 <Souri> q+
15:29:27 <pchampin> :graph :hasTriples (<<( s p o )>> <<(s' p' o' )>>).
15:29:27 <gkellogg> ack pchampin
15:29:32 <niklasl> +1 for that example
15:29:42 <pchampin> ack AndyS
15:30:01 <gkellogg> AndyS: The other thing about lists is they have to be bnodes to preserve merging.
15:30:11 <pchampin> ack Souri
15:30:39 <gkellogg> Souri: Remember we restrict RDF triple terms such that they can only be the object of rdf:reifies.
15:30:41 <AndyS> Containers have other issues: too many triples - or rather too obviously a triples structure. They are nice(ish) in RDF/XML. Turtle had list syntax from day one.
15:31:15 <gkellogg> ... We would be going against that restriction if we introduce lists.
15:31:48 <pchampin> q?
15:32:07 <tl> q+
15:32:12 <gkellogg> ... If you could say rdf:reifies (<<|...|>>, <<|..|>>) we could use this for different modeling purposes.
15:32:24 <gkellogg> pchampin: Maybe we should use a different predicate.
15:32:48 <pchampin> ack tl
15:33:15 <gkellogg> tl: If we have :e1 reifies ..., we could be explicit about what annotations refer to.
15:33:37 <TallTed> RRSAgent, draft minutes
15:33:38 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html TallTed
15:33:44 <gkellogg> Souri: Maybe rdf:refiiesSet as a predicate.
15:34:26 <gkellogg> zakim, end meeting
15:34:26 <Zakim> As of this point the attendees have been souri, gkellogg, niklasl, TallTed, tl, AndyS, enrico, fsasaki, pfps
15:34:28 <Zakim> RRSAgent, please draft minutes
15:34:30 <RRSAgent> I have made the request to generate https://www.w3.org/2024/04/12-rdf-star-minutes.html Zakim
15:34:36 <Zakim> I am happy to have been of service, gkellogg; please remember to excuse RRSAgent.  Goodbye
15:34:36 <Zakim> Zakim has left #rdf-star
15:34:45 <gkellogg> rrsagent, bye
15:34:45 <RRSAgent> I see no action items