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OWL Working Group Meeting Minutes, 04 June 2008

DRAFT. Currently Under Review

See also: IRC log

Bijan Parsia: 54 minutes ago?

Bijan Parsia: Grr. Why not?

Peter Patel-Schneider: sorry, bijan, I cannot answer that question when only one person is present

Sandro Hawke: (hi...)

Bijan Parsia: If only....

Bijan Parsia: We need a chair, eh?

Uli Sattler: alan should be chairing?
Ivan Herman: ????
Bijan Parsia: He doesn't seem to be here,yes?

(Scribe changed to Elisa Kendall)

Bijan Parsia: He's listed as chair

Bijan Parsia: Ian is on vacation

Bijan Parsia: I have the popular vote in non-caucus states...
Uli Sattler: did anybody emailed/pinged Alan?
Bijan Parsia: He's not on skype
Sandro Hawke: I'll swing by his office on my way.

Sandro Hawke: (never mind)
Bijan Parsia: ...and since he's so very dillegent, I can't imagine anything but physical injury would keep him from attending!
Alan Ruttenberg: hi
Bijan Parsia: So, sandro, stop your harshing on alan!

(No activity for 37 minutes)

Alan Ruttenberg: q?
Uli Sattler: ...and bottom role is easy anyway

you put it into one of our reasoners, you see whether or not it can be done ... let's just do this

Alan Ruttenberg: ack bijan

Boris Motik: q+

there is different motivation for these, for keys it's a huge wart on the language, but we can request implementation and see what happens

so there is always a wide balance of considerations, and no one was trying to suggest otherwise

Alan Ruttenberg: ack alnr

whether we keep this on a separate page or include them is a different issue now -- we're at the implementation stage and need to see whether or not we can do them

Uli Sattler: s/keyes/keys

Alan Ruttenberg: would there be any strong objectors to dropping top and bottom role? do you think there isn't any reason to spend more time on them?

Carsten Lutz: yes
Sandro Hawke: +0.5 keep top and bottom
Peter Patel-Schneider: no - no strong objection from me to not including top/bottom

If you say yes then you really want them

Markus Krötzsch: +0.5 to top
Ivan Herman: 0
Boris Motik: +1 to investigate top and bottom


Uli Sattler: +0.3 would be a shame if we dropped them unnecessarily
Michael Schneider: 0
Rinke Hoekstra: +0.5 to have top
Achille Fokoue: 0
Markus Krötzsch: (+1 to not drop something based on theoretical performance considerations)

Alan Ruttenberg: so it's been mentioned several times, so regardless of whether we put something into the spec, we will need 2 implementations

Ivan Herman: oops, lost our boss

Alan Ruttenberg: hang on
Uli Sattler: Alan went!

Peter Patel-Schneider: alan is lost in the fog :-)
Rinke Hoekstra: +1 MarkusK
Uli Sattler: Can we go as well?

Bijan Parsia: Hello!
Zhe Wu: that is strange

Uli Sattler: Alan got taken over by Aliens!

Alan Ruttenberg: so I'm wondering whether we should resolve such problems by saying that we should put these things in and see what happens, or not

Bijan Parsia: I'd prefer for things to get into Working Drafts

the advantage of putting them in is that folks have something to think about for longer

Sandro Hawke: "at risk"
Uli Sattler: sounds fine

Sandro Hawke: the W3C key is to say that something is at risk, then if you take it out later you don't have to worry about the process

Boris Motik: q+
Alan Ruttenberg: q?
Bijan Parsia: If something is not labeled at risk and gets pulled out, the default is to go back to last call
Alan Ruttenberg: ack bmotik

Boris Motik: I don't think that discussing this over email would be useful -- my proposal would be to implement these features and then come back and say yes this was the experience

Evan Wallace: do we have volunteers to implement?
Evan Wallace: applauds Boris as well!
Bijan Parsia: I'm experiementing with Top and Bottom
Bijan Parsia: And some easy key stuff as well

my proposal would be to postpone this for a week, 2, 3 and then see what really happens ... in my case the implemetnation isnt really there so it would be a month before I could come back with an answer

Bijan Parsia: We can always mark them in WDs as "needing implementor feedback"

Alan Ruttenberg: we should discuss next week whether or not we should put things that are at risk into the spec

Issue Discussions

Alan Ruttenberg: q?
Boris Motik: It's not Issue 108; it's a thing that doesn't have an issue
Boris Motik: q+
Alan Ruttenberg: ack bmotik

Alan Ruttenberg: Issue 108 -- i sent out mail to the W3C space to see what was there and there seemed to be some relevant things about how we should be using the keywords (should, must)

Boris Motik: I also looked in one of these RFCs, regarding "should" and i wasnt happy with that because it says this is optional, and I would like something more than optional

Bijan Parsia: SHOULD, in practice, varies in its strength
Alan Ruttenberg: 3. SHOULD This word, or the adjective "RECOMMENDED", mean that there
Alan Ruttenberg: may exist valid reasons in particular circumstances to ignore a
Alan Ruttenberg: particular item, but the full implications must be understood and
Alan Ruttenberg: carefully weighed before choosing a different course.
Bijan Parsia: q+
Alan Ruttenberg: 4. SHOULD NOT This phrase, or the phrase "NOT RECOMMENDED" mean that
Alan Ruttenberg: there may exist valid reasons in particular circumstances when the
Alan Ruttenberg: particular behavior is acceptable or even useful, but the full
Alan Ruttenberg: implications should be understood and the case carefully weighed
Alan Ruttenberg: before implementing any behavior described with this label.

we've been using this to say something is default ... do it like this unless you have a very good reason for not doing it

Alan Ruttenberg: q?

Bijan Parsia: it doesn't mean optional ...

Michael Smith:

Bijan Parsia: That was sandro :)

Boris Motik: then I looked at a different document

Boris Motik: +q

Bijan Parsia: the official definition is what you were asking for, but in general, "should" can have the effect of being optional, or could have the effect of being mandatory, depending on how you read it

Alan Ruttenberg: q?
Alan Ruttenberg: ack bijan
Evan Wallace: We SHOULD use SHOULD an interpret it as Alan quoted under 3 (Boris' meaning)

If we are going to have shoulds, then we can use it as specified in the RFC -- shoulds are compatibility points

Boris Motik: as we are using it, the meaning is exactly as in the RFC, so perhaps we should repeat it

I don't think we will be using other keywords

if you are departing from this default, you should advertize it clearly

Bijan Parsia: "Warnings"

the inventor is obliged to say what he really did there

Alan Ruttenberg: q?
Alan Ruttenberg: ack bmotik
Sandro Hawke: +1 boris, yes we can/should require vendors to be clear about when they are exercising a SHOULD.
Bijan Parsia: q+
Alan Ruttenberg: ack bijan
Alan Ruttenberg:

Alan Ruttenberg: the only question I have is that the manuals say how to do this and make it typographically visible - is there any reason we shouldn't do that

in the w3c manual, it says explicitly how to use them

Sandro Hawke: "conformance labels"
Boris Motik: +q

Bijan Parsia: this idea that we should have some kind of --- from vendors we should talk about some notion of conformance, and that we could ask that warnings be given in some form or another

we havent done any of that yet

Alan Ruttenberg: if you could put an issue in for this, it's distinct from what we're discussing and useful

Bijan Parsia: we do!

Boris Motik: if people really depart from these things, it has to be clear that an implementation is really departing from the "should"

Bijan Parsia: q+
Sandro Hawke: I think we can require warnings.

Alan Ruttenberg: ack bmotik
Alan Ruttenberg: q+ alanr
Alan Ruttenberg: ack bijan

it would be useful for the implementer to say what part of the shoulds they did not implement; if a vendor says they are compliant, they should say that they are OWL 2 compliant BUT ...

Boris Motik: +q
Boris Motik: -q

Bijan Parsia: among our options are conformance labels, warnings ... and we can choose what we say about these, similar things occur in other W3C specifications - we can say that in order to conform with OWL 2 you must adhere to the shoulds ...

Boris Motik: I agree that the last thing you said is just a conformance label and I've put this into the spec

Alan Ruttenberg: ack alanr

Alan Ruttenberg: the issue is if we are going to use "SHOULD" then we should follow the advice of the TR with respect to how we use them; if we are going to talk about conformance levels, that's an interesting and separate issue that we should put in and take up at another meeting

Bijan Parsia: Issue 130 has been raised

we also need to cite it as a reference and do the other things they say we need to do

Alan Ruttenberg: q?

Alan Ruttenberg: Issue 97 - we decided that we would write up a short doc about how to handle GRDDL for the OWL XML syntax; the issue is regarding who would take up this document development

Bijan Parsia: Ok
Sandro Hawke: ivan! ivan!

Action on Bijan to write up this point of view

Bijan Parsia: I could do it :)
Bijan Parsia: I won't be at the f2f either
Bijan Parsia: I can write the pro case!

It would be good to have one of the W3c guys write up something on how to do this using XSLT

I want to get someone to commit to the writing

Alan Ruttenberg: Ivan would you write up the first draft?

Ivan Herman: ok

on irc or the wiki

Ivan Herman: s/irc/email/

ACTION: bijan write 1/2 of GRDDL pro/con document for presentation and vote in next f2f

trackbot (guest): Created Action 154 - Write 1/2 of GRDDL pro/con document for presentation and vote in next f2f [on Bijan Parsia - due 2008-06-11].
Alan Ruttenberg: ivan write 1/2 of GRDDL pro/con document for presentation and vote in next f2f, Sandro to own it at F2F

ACTION: ivan write 1/2 of GRDDL pro/con document for presentation and vote in next f2f, Sandro to own it at F2F

trackbot (guest): Created Action 155 - Write 1/2 of GRDDL pro/con document for presentation and vote in next f2f, Sandro to own it at F2F [on Ivan Herman - due 2008-06-11].
Bijan Parsia: Can I get a pointer ot hte discussion last week?
Bijan Parsia: I'mahving trouble finding it
Peter Patel-Schneider: I'm happy to talk about 124

Alan Ruttenberg: Issue 124 - should we discuss this

Alan Ruttenberg: agreed to

Bijan Parsia: I'm confused about what I should be writing up on GRDDL - need a little context, but it came from the discussion two weeks ago

Sandro Hawke: the process could be that Bijan writes it, and everyone screams, or Alan writes it and everyone screams -- Sandro will provide the context to Bijan with regard to how to resolve this

Ivan Herman: :-0

from the minutes two weeks ago

Alan Ruttenberg: we were going to have a formal vote on this ...

Bijan Parsia: so where does that leave us?

Alan Ruttenberg: I would rather have Bijan contribute the piece he needs to create, and then have Ivan do the same with the other side

Peter Patel-Schneider: q+

Sandro Hawke: two weeks ago discussion:

Issue 124

Peter Patel-Schneider: q+ to note that the "related notes" in the issue appear to be incorrect, ...

Alan Ruttenberg: peter - agree, my mistake - will fix

Michael Schneider: the issue is for OWL Full in the current semantics, the complement is relative to the whole domain, and the problem is that all datatypes, or all subsets of RDFSLiteral ...

the currently used URI for this is overloaded

Alan Ruttenberg: ack pfps
Zakim: pfps, you wanted to note that the "related notes" in the issue appear to be incorrect, ...

there are two domains for this in OWL DL but only one domain in OWL Full

Michael Schneider: what i am talking about here is actually a distinct issue, which just came up in the discussion of 124
Alan Ruttenberg: q?

Alan Ruttenberg: originally, when we talked about complement of datarange, when we talked about the complement of 5 integer, you got all other integers ... but then Boris said that the complement would include all other datatypes, not just integers

Michael Schneider: what i propose is to just give it a strict name for this other complement

Alan Ruttenberg: q?

this is different from Issue 124 -- it is much easier to fix, all we need to do is provide an owl data complement uri

this came up during the discussion of Issue 124

Michael Schneider: this is an RDF mapping issue [Scribe assist by Michael Schneider]

Alan Ruttenberg: my thought is to include this in the same issue, rather than opening another issue

Michael Schneider: thanks, peter ;-)

Peter Patel-Schneider: Michaels solution for this is perfect

Alan Ruttenberg: Michael, would you come up with a solution of this for our agenda for next week?

Michael Schneider: yes, I'll do that

Alan Ruttenberg: q?
Ivan Herman: q+

Alan Ruttenberg: Issue 109 is a question of what namespace to use for the OWL XML schema, and whether or not it should be distinct from or the same as what we're using for the RDF/XML OWL namespace

Alan Ruttenberg: ack ivan
Ivan Herman:
Bijan Parsia: I'm not so pessimistic either
Bijan Parsia: Or homicide!

Ivan Herman: I have written up some of the discussion I had yesterday with Bijan, but I am not as pessimistic about this as you are. I tried to write down what the choice is and next week we can vote on this and people can choose between the two options. It's not that big of a deal

Alan Ruttenberg: that's fine with me unless anyone has anything else to add

Alan Ruttenberg: put 109 on agenda for next week - all to read

Additional Other Business

Alan Ruttenberg: we have a mail from a user asking about horn shiq and about why it's not in owl ... how should we respond

Bijan Parsia: hornSHIQ is a good profile!

Alan Ruttenberg:$9cd57cc0$d6807640$@com
Carsten Lutz: He is within OWL2 DL

Bijan Parsia: is there any reason not to include it as one more profile?

Uli Sattler: ...there was "too many profiles"
Michael Smith: +1 to uli's recollection

depending on whether you count 3 or 5 or 7, depending on how you count the full versions of the little ones ...

Carsten Lutz: q+

Bijan Parsia: hornshiq is a distinct and interesting profile, so would this open the floodgates? there is a user who wants this ...

Alan Ruttenberg: ack Carsten
Bijan Parsia: q+

Carsten Lutz: if we want to consider adding this, is it interesting enough to become rec? that's not a very strong point for adding it - we already have one data complexity profile, so I'm not really convinced

Alan Ruttenberg: ack bijan
Peter Patel-Schneider: +1 to carsten

Carsten Lutz: That applies to every user
Markus Krötzsch: +1 to Carsten
Alan Ruttenberg: q+

Bijan Parsia: the other thing is that there are modeling problems that fall into hornSHIQ that are not relevant to the other data complexity profile - that's where he's coming from

otherwise i agree with you in general

Alan Ruttenberg: ack alanr
Carsten Lutz: q+

but Christian was coming from both a modeling and performance perspective

Carsten Lutz: I disagree

Alan Ruttenberg: I wonder if we should have the requirements people capture the modeling issue

Alan Ruttenberg: ack Carsten
Uli Sattler: +1 to Carsten's recollection

Carsten Lutz: I disagree, because that something was good for modeling is not a good reason to include something - there should be an additional virtue that it has when you don't use DL full

Alan Ruttenberg: q+ to say perhaps I mispoke
Ivan Herman: +1 to Carsten
Alan Ruttenberg: ack alanr
Zakim: alanr, you wanted to say perhaps I mispoke

Carsten Lutz: ok

Alan Ruttenberg: I meant modeling in the sense of the inference you could make from it -- and whether the use case was compelling enough and the performance gain compelling enough to consider

Bijan Parsia: Well, hornSHIQ can be compiled to (potentially exponentially many) datalog rules. KAON2 shows that performance (in that case) is pretty reasonable. In that sense, it's sort ofa "maximal" DLP
Carsten Lutz: maximal in OWL*2*?
Bijan Parsia: So we could respond: It's unclear that hornSHIQ is a profile that will have enough implementor and user support to be a viable profile, esp. given how many fragments we already have. If you would like the WG to reconsider, could you provide some more information...
Bijan Parsia: Carsten, ooo, dunno

so - we have on one hand some people are saying well use OWL DL, we have too many fragments already and it isn't sufficiently compelling; the alternative would be to say we will investigate a little more and you shoudl talk with our requirements people about it

Uli Sattler: +1 to Bijan
Uli Sattler: Bijan's first suggestion!
Ivan Herman: +1 to bijan
Diego Calvanese: +1 to Bijan
Peter Patel-Schneider: +1 to bijan
Zhe Wu: +1 to bijan
Alan Ruttenberg: +1
Achille Fokoue: +1 to bijan

Alan Ruttenberg: I like what Bijan says -

Michael Smith: +1
Rinke Hoekstra: +1
Carsten Lutz: +1
Bijan Parsia: +1 to me
Markus Krötzsch: +1
Evan Wallace: +1
Bijan Parsia: Chair response

Ivan Herman: I think Alan should respond

ACTION: Alan to respond to the email along the lines Bijan suggests above

trackbot (guest): Created Action 156 - Respond to the email along the lines Bijan suggests above [on Alan Ruttenberg - due 2008-06-11].

Alan Ruttenberg: last item -- Bijan brought up the issue of accessibility guidelines, and the work that needs to be done to follow those guidelines in our documents

Bijan Parsia: q+

what work needs to be done, how do we get started

Alan Ruttenberg: ack bijan

Sandro Hawke: I know there is something to be done but don't know how much work it is

Rinke Hoekstra:
Ivan Herman: q+

Bijan Parsia: it's certainly the case that for our images we need to have alternate text, tables are often hard for assisted technology without additional mark-up

Michael Schneider: unless there is no official W3C policy on this (is there any?), are we supposed to do anything in this direction?
Alan Ruttenberg: q?

there may be work to be done to make sure that the tables are good enough

Uli Sattler: michael, I think we should

there are some tools that check from an accessibility point of view

Bijan Parsia: ALl our javascript dumbs down well

Ivan Herman: I don't know how extensively we use java scripting - that would require some additional explanation in the text

Uli Sattler: Sandro, what does W3C normally do?

Alan Ruttenberg: it seems like we need some research on this, and someone to review our documents ... maybe we can discuss on the chairs list how we can get additional information and get back to the group with some harder facts

Alan Ruttenberg: AOB?

Uli Sattler: bye bye
Markus Krötzsch: bye

Rinke Hoekstra: bye

Diego Calvanese: bye
Michael Schneider: bye
Ratnesh Sahay: bye
Zhe Wu: bye

ACTION: Alan to confer with chairs list about how to get more information about what we need to do re: accessibility

trackbot (guest): Created Action 157 - Confer with chairs list about how to get more information about what we need to do re: accessibility [on Alan Ruttenberg - due 2008-06-11].
Diego Calvanese: quit

Diego Calvanese: #quit