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13:00:11 <trackbot> RRSAgent, make logs rdf-data-shapes
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13:00:13 <trackbot> Zakim, this will be SHAPES
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13:00:14 <trackbot> Meeting: RDF Data Shapes Working Group Teleconference
13:00:14 <trackbot> Date: 08 March 2017
13:00:43 <hknublau> present+
13:00:52 <Dimitris> present+
13:01:25 <ipolikof> present+
13:01:32 <dallemang> present+
13:02:00 <pano> pano has joined #shapes
13:03:27 <ipolikof> chair: ipolikof
13:04:13 <ipolikof> scribenick: dallemang
13:04:35 <pano> present+
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13:04:39 <sandro> present+
13:05:03 <dallemang> ipolikof:  Approve minutes
13:05:09 <ipolikof> PROPOSED: Approve minutes of the 01 Mar 2017 Telecon: https://www.w3.org/2017/03/01-shapes-minutes.html
13:05:26 <ipolikof> +1
13:06:05 <hknublau> +1
13:06:11 <dallemang> dallemang: is it important to change minutes for dallemang  being present
13:06:14 <pano> +1
13:06:22 <TallTed> present+
13:06:22 <dallemang> sandro: not importat to change, since dallemang shows up in ballots
13:06:24 <ipolikof> RESOLUTION: Approve minutes of the 01 Mar 2017 Telecon: https://www.w3.org/2017/03/01-shapes-minutes.html
13:06:29 <dallemang> +1
13:06:48 <dallemang> ipolikof: agenda: disposal of isssues.  No open issues
13:07:00 <dallemang> ipolikof: Introduces pfps as special guest
13:07:21 <dallemang> ipolikof: pfps will explain his objections
13:07:48 <ipolikof> https://www.w3.org/2014/data-shapes/wiki/FO-1:Removing_features_from_node_shapes
13:07:55 <dallemang> pfps: We can do this foromulaic, or to do something good.  Which will we do?
13:08:10 <dallemang> TallTed: We are all trying to achieve something successful, with best results
13:12:36 <dallemang> pfps: he can discuss the three formal objections, vs. general problems he sees with working group operation.  pfps thinks that the latter is more productive
13:13:18 <dallemang> ipolikof: wants to go through the objections to understand them.
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13:17:35 <dallemang> ipolikof: and pfps  objections were described on a tight deadline
13:18:24 <dallemang> pfps: starting with https://www.w3.org/2014/data-shapes/wiki/FO-1:Removing_features_from_node_shapes
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13:19:50 <dallemang> pfps: removal removes expressive power, further complicates language,
13:20:43 <dallemang> pfps: lost expressive power threatens future-proofing
13:22:16 <dallemang> ipolikof: to clarify: Loss of expressive power has to do with future possibliity of subject becoming literals?
13:22:26 <dallemang> pfps: Not sure that this is true
13:23:08 <dallemang> ipolikof: was pfps member of that rdf working group?  yes, he was.  Did he raise objection to that?  No, that group was chartered for minor changes.
13:23:21 <dallemang> ipolikof: can you talk about machine generated shapes?
13:24:30 <dallemang> pfps: eg., transform DL into shapes.  There is already a commercial system that does something like this.   This could use a SHACL engine to run this.
13:25:01 <sandro> (stardog icv)
13:25:06 <dallemang> pfps: Stardog is the commercial system
13:26:07 <dallemang> pfps: some DLs allow a /self/ role (Stardog doesn't), so /self/ role restrictions turn into node shapes.
13:26:22 <dallemang> ipolikof: can you send us some OWL constructs that cause this issue?
13:27:39 <dallemang> pfps:        "at least 2 self Person"
13:28:16 <dallemang> ipolikof: Have you seen this in practice?  (asking about pfps
13:28:30 <dallemang> ipolikof: have you seen this in practice?
13:28:50 <dallemang> pfps: Yes, at least one widely, OpenCyc in OWL that uses necessarily empty concepts as part of OWL trnaslation
13:29:52 <dallemang> sandro: unconfirmed suspicion is that the loss of power has to do with use of generalized RDF.  pfps  confirms that he believes this to be the case
13:30:24 <ipolikof> https://www.w3.org/2014/data-shapes/wiki/FO-2:Disjoint_siblings
13:30:29 <dallemang> ipolikof: Next one https://www.w3.org/2014/data-shapes/wiki/FO-2:Disjoint_siblings
13:31:18 <dallemang> pfps: hasn't had enogh time to look at latest edit
13:31:53 <dallemang> pfps: earliest time to look at it is March 20
13:32:12 <ipolikof> https://www.w3.org/2014/data-shapes/wiki/FO-3:No_requirement_to_reject_graphs_with_invalid_shapes
13:32:15 <sandro> (week of March 20)
13:32:19 <dallemang> move on to https://www.w3.org/2014/data-shapes/wiki/FO-3:No_requirement_to_reject_graphs_with_invalid_shapes
13:32:36 <dallemang> pfps: this page misses the major point
13:33:19 <dallemang> pfps:  The issues is that it is possibe to build a SHACL graph in such a way that users don't know how they interact with others.    There is no way to know if your grpah is valid or not.
13:33:41 <dallemang> pfps: Rules for validity are difficult - so it is difficult to know if the graph is valid
13:34:22 <dallemang> pfps: implementations are free to do as they please with invalid graphs.  With no indication back to the user.
13:34:35 <Nicky> present+
13:34:47 <dallemang> pfps: this is fatal to interoperability
13:34:52 <dallemang> q+
13:36:05 <dallemang> pfps: "Usrs of conforming SHACL implementations will have no way to know if their graphs will be processed the same way in other implementations"
13:36:21 <dallemang> pfps: this is because even for valid grpahs, they don't know if they are valid
13:36:29 <sandro> q+
13:38:29 <sandro> dalleman: This issue sounds clear and valid, but I thought we dealt with this 2-3 weeks ago.  Did that get reflected in draft?
13:38:30 <dallemang> dallemang: Didn't we talk about this two or three weeks ago?
13:39:18 <dallemang> pfps: the change was to allow implemetnations to signal whether it is valid?
13:39:26 <dallemang> pfps: key problem is "allow" - so it might now
13:40:25 <dallemang> sandro: finds this compelling, and of course, we'll  stick to valid graphs, but for users, there will be mistakes
13:40:28 <TallTed> q+
13:40:34 <sandro> ack sandro
13:40:36 <dallemang> pfps: even with expert users we'll have these mistakes
13:41:14 <dallemang> ipolikof: what is the amount of work we'll need to make it happen?
13:41:31 <dallemang> pfps: a one-word change will be sufficient, i.e., allow -> require
13:41:52 <dallemang> pfps: WG has to write tests so that the implementation can do this
13:42:11 <hknublau> ack dallemang
13:42:12 <dallemang> sandro: invalid shapes definition and tests will be needed
13:42:17 <hknublau> ack sandro
13:43:08 <hknublau> ack TallTed
13:43:14 <dallemang> TallTed: Recalls this as a requirement for a linter, akin to the ones we see for RDF and OWL, none of which are required by a SPARQL engine.  But Validator is there (instead of the engine)
13:43:36 <dallemang> sandro: HTML5 fixed this by defining repair behaviors (HTML5 had a problem like this)
13:44:02 <dallemang> TallTed: Does this really work on all HTML5 failure mode?
13:44:18 <dallemang> sandro: No, just that this is viewed as an error, and was addressed this way
13:44:33 <dallemang> q+
13:45:05 <hknublau> ack dallemang
13:46:04 <dallemang> ipolikof: we have worried that this raises the bar for implementation.  Is that unreasonably high?
13:46:58 <dallemang> sandro: maybe a middle ground?  The implemetnation is only required to reject the errors that SHACL itself can check (e.g., a shape for SHACL)?
13:47:14 <dallemang> ipolikof: for Core, many things could be checked by SHACL itself (with a SHACL Shape for SHACL)
13:47:24 <dallemang> sandro: presumably this bar is pretty low
13:47:40 <dallemang> pfps: the code to do the check isn't much, he's done it, two pages of code
13:48:48 <dallemang> pfps: also, it is possilbe to check all of CORE easily, except   sh:pattern be legal SPARQL , and recursive for paths and shapes, but can be checked with an extension to core that only takes a small implementation change.
13:48:56 <dallemang> pfps: that is, bar is low
13:49:17 <dallemang> pfps: has sent comments to this effect to the group (can we find these in our archives?)
13:50:18 <dallemang> dallemang: I think there might be a proposal we could do from this to resolve it.
13:50:27 <dallemang> ipolikof: this is an info gathering call
13:50:50 <sandro> q+
13:52:14 <dallemang> sandro: There is more going on here than just allow -> require.  There will have to be some sort of mode, etc.
13:52:34 <dallemang> sandro: strict vs loose for instance
13:52:54 <dallemang> pfps: that was pfps' proposal
13:53:13 <dallemang> pfps: strict checking is cheap, do ti all the time, but a loose mode is permissible.
13:53:27 <sandro> ack sandro
13:53:43 <dallemang> ipolikof: move on to other topics from pfps
13:54:01 <dallemang> pfps: structurat topics.  He has sent into to group that hasn't received responses
13:54:24 <dallemang> pfps: many comments have only received non-technical responses
13:54:44 <dallemang> pfps: it is the WG's job to respond to comments.
13:55:04 <dallemang> TallTed: WG's job is to wokr, there are lots of kinds of work
13:55:46 <dallemang> ipolikof: regarding pfps' email about implemnting syntax check
13:56:21 <dallemang> ipolikof: isn't "thank you for the info" appropriat?
13:56:25 <dallemang> pfps: for this, yes
14:00:48 <dallemang> TallTed: WG is doing its best to keep up with comments,  If we aren't keeping up, we need to go to W3C mgmt, who has asked for issues to be triaged
14:02:33 <dallemang> pfps: this is a lot of work for pfps to figure out whether changes to the doc have really addressed a comment.
14:05:19 <dallemang> sandro: can github help us manage this?
14:05:23 <dallemang> pfps: Probably not
14:05:35 <dallemang> pfps: this seems like more burden on the commenter
14:06:55 <dallemang> pfps: sometimes a comments become an issue, and the issue is closed, but he doesn't necessarilly know how it was closed so that he can evaluate if it was responsive
14:07:15 <dallemang> sandro: github model keeps a trail for this
14:08:15 <dallemang> ipolikof: this isn't about checking the WG process, but really about the issues and comments on SHACL spec as it is now.
14:09:20 <sandro> q+
14:09:24 <dallemang> ipolikof: do we need to track all the back issues, or review the spec as it stands today?
14:10:38 <dallemang> sandro: process from other groups - if an issue was closed,  we only raise it again if there is something new
14:13:43 <sandro> PROPOSED: In the transition request, we'll be clear that the door is open during CR for any issues that were previously reported and handled in a way which was not fully reported back to the commenter
14:14:53 <dallemang> pfps: treating the doc as new and looking for issues again is difficult for reviewers, and risks dropping issues through the cracks
14:17:29 <TallTed> +1
14:17:36 <sandro> +1
14:17:46 <ipolikof> RESOLUTION: In the transition request, we'll be clear that the door is open during CR for any issues that were previously reported and handled in a way which was not fully reported back to the commenter
14:17:48 <sandro> pfps: Or in status of document
14:19:10 <dallemang> +1
14:19:20 <pano> +1
14:21:18 <dallemang> pfps: pre-binding has been and continues to be a problem, is it well-behaved?
14:21:55 <dallemang> pfps: it isn't his job to convince anyone that it works, since pfps isn't a pre-binding advocate.
14:23:23 <dallemang> ipolikof: Andy Seaborne is not on the call today, who could respond to this.
14:24:09 <sandro> q+
14:26:20 <dallemang> TallTed: This is an early release, and the process is iterative
14:31:46 <dallemang> ipolikof: Andy is a recognized expert in SPARQL
14:31:56 <dallemang> pfps: reluctantly agrees
14:32:04 <sandro> q+
14:32:10 <dallemang> pfps: we need someone who can review Andy's work
14:34:52 <dallemang> sandro: there's an academic idea of "peer review" - e.g.,, three reviewers for any item.
14:35:40 <dallemang> sandro: this process is less than that.
14:36:00 <dallemang> pfps: pre-binding has had many iterations, and required shouting from pfps to get any attention at all.
14:37:18 <dallemang> pfps: pre-binding history:  SHACL wanted pre-binding, and said "use SPARQL", but the SPARQL spec didn't have details of the meaning, so we couldn't find out what it means.
14:38:06 <dallemang> ipolikof: if this objection were raised for SPARQL, would it have made it to CR?
14:38:46 <dallemang> pfps: there is no implementation of SPARQL
14:39:04 <dallemang> ipolikof: but it is successful and there are many implementations
14:40:01 <dallemang> pfps: here are probably ways to fix it up, and Andy could do that.
14:40:19 <dallemang> pfps: what will we do if a problem is found?
14:40:54 <sandro> Zakim, who is here?
14:40:54 <Zakim> Present: hknublau, Dimitris, ipolikof, dallemang, pano, sandro, TallTed, Nicky
14:40:56 <Zakim> On IRC I see TallTed, pano, Zakim, RRSAgent, ipolikof, hknublau, Dimitris, dallemang, pfps, sandro, rhiaro, trackbot
14:41:08 <dallemang> ipolikof: personal opinion, if SHACL reaches the success level of SPARQL, she's happy, hope for even more success
14:41:25 <dallemang> ipolikof: that would address industry needs.   Maybe not perfect.
14:42:04 <dallemang> pfps: WG can move ahead with this unknown
14:42:15 <dallemang> pfps: Another topic.  Validation Reports
14:43:12 <dallemang> pfps: made an earlier objection, and sees that the pendulum has swung the other way
14:43:46 <dallemang> pfps: it will be possible to produce validation reports that vary from the expectation.
14:45:04 <dallemang> pfps: suspects that there are issues, but he hasn't had time to find it.
14:45:17 <dallemang> pfps: WG could deicde to wait for pfps , which won't be for a few weeks
14:46:23 <dallemang> sandro: checking against the test suite will reveal problems
14:46:32 <dallemang> pfps: assuming that test suite can check it, which is hard
14:46:46 <dallemang> ipolikof: test suite will include validation report
14:46:53 <sandro> If the test suite compares validation reports, this problem should be addressed
14:48:13 <dallemang> pfps: if writing the tests reveals the issue, then we make a new CR at that level
14:49:14 <dallemang> sandro: has the WG resolved that the test suite should include validation reports ?
14:49:31 <dallemang> ipolikof: No formal resolution. OPTIONAL things might not be in
14:50:11 <dallemang> hknublau: test harness checks output graph isomorphism between output and expectation
14:50:26 <dallemang> pfps: not sure that graph isomorphis is correct test
14:51:36 <dallemang> pfps: we have to include "we will check validation reports as part of the test"
14:54:28 <dallemang> sandro: are you asking for something beyond standard requirement, that if two people implement to the spec, then they can interoperate?
14:54:53 <dallemang> ipolikof: W3C director has a lower bar - need a test suite, needs to be reasonable, might not be comprehensive
14:55:23 <sandro> sandro: Every normative statement in the spec should result in 1+ tests
14:55:26 <dallemang> pfps: every normative statement should have something backing it up
14:55:51 <dallemang> pfps: end of major things, he's concerned with syntax
14:56:16 <dallemang> pfps: current syntax is mystifying
14:56:35 <dallemang> pfps: disjoint shapes is worrisome
14:56:53 <dallemang> pfps: theres still a lot of work to be done, and this is nobody's day job.
14:57:41 <dallemang> ipolikof: misalignment between pfps' expectation and WG process, and even W3C process
14:58:50 <dallemang> ipolikof: time is up.  to sandro  is there any urgent process issue/
14:59:46 <dallemang> sandro: internationalization email
14:59:51 <dallemang> ipolikof: i think that was good
15:00:56 <TallTed> RRSAgent, draft minutes
15:00:56 <RRSAgent> I have made the request to generate http://www.w3.org/2017/03/08-shapes-minutes.html TallTed
15:01:00 <TallTed> RRSAgent, make logs public
15:01:11 <TallTed> trackbot, end meeting
15:01:11 <trackbot> Zakim, list attendees
15:01:11 <Zakim> As of this point the attendees have been hknublau, Dimitris, ipolikof, dallemang, pano, sandro, TallTed, Nicky
15:01:19 <trackbot> RRSAgent, please draft minutes
15:01:19 <RRSAgent> I have made the request to generate http://www.w3.org/2017/03/08-shapes-minutes.html trackbot
15:01:20 <trackbot> RRSAgent, bye
15:01:20 <RRSAgent> I see no action items