Chatlog 2009-07-28

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<LeeF> Present: Lee, eric, Axel, Alex, kjetil, john-l, kasei, pgearon, SimonS, Andy, luke, bglimm, ivanh, simonkj, prateek
13:58:10 <trackbot> Meeting: SPARQL Working Group Teleconference
13:58:10 <trackbot>  Date: 28 July 2009
13:58:11 <Zakim> SW_(SPARQL)10:00AM has now started
14:02:54 <LeeF> Regrets: Bijan, SteveH, Chime
14:02:54 <LeeF> Chair: AxelPolleres
14:04:12 <AxelPolleres> topic: Admin
14:04:12 <AxelPolleres>
14:04:37 <AxelPolleres> scribe: Eric
14:04:50 <AxelPolleres> scribenick ericP
14:06:03 <AndyS> Agenda points to 2009-07-14
14:06:13 <AxelPolleres> PROPOSED: accept minutes
14:06:45 <AxelPolleres> RESOLVED: accept minutes
14:07:20 <kasei> sure
14:07:22 <pgearon> pgearon has joined #sparql
14:07:30 <AxelPolleres> greg to scribe next week.
14:07:44 <Zakim> + +1.216.445.aaee
14:07:49 <john-l> Zakim, aaee is me
14:07:49 <Zakim> +john-l; got it
14:08:02 <ericP> topic: Liaisons
14:08:02 <Zakim> + +1.312.863.aaff
14:08:15 <ericP> ericP: nothing to report from HCLS or XQuery
14:08:24 <pgearon> Zakim, aaff is me
14:08:24 <Zakim> +pgearon; got it
14:08:27 <ericP> AxelPolleres: nothing to report from RIF
14:08:59 <AxelPolleres> no news from liaisons
14:09:02 <AxelPolleres> topic: Actions
14:09:32 <AxelPolleres>
14:09:42 <AxelPolleres> continued
14:10:09 <AxelPolleres> continued
14:10:16 <SimonKJ> I have started to get 403 errors on the wiki, it worked 10 minutes ago
14:10:41 <AxelPolleres> 
14:10:55 <SimonKJ> all
14:11:07 <SimonKJ> I had loaded the agenda first thing, I just hit reload and got 403
14:11:35 <SimonKJ> hopefully a temporary glitch, just be nice to see the action/issue list
14:11:42 <AxelPolleres>
14:11:55 <AxelPolleres> done
14:12:03 <pgearon> +q
14:12:14 <AxelPolleres> done
14:12:29 <LukeWM>
14:12:36 <AxelPolleres> done
14:13:15 <AxelPolleres> done
14:14:19 <AxelPolleres> action-55 continued!
14:13:45 <kjetil_> q+ to propose that F&R should be early in the meeting
14:14:07 <LeeF> q+ to ask about vis a vis
14:14:16 <kjetil_> ack pgearon
14:14:26 <kjetil_> ack me
14:14:27 <Zakim> kjetil_, you wanted to propose that F&R should be early in the meeting
14:16:12 <kjetil_> Zakim, mute me
14:16:12 <Zakim> kjetil_ should now be muted
14:16:24 <AxelPolleres> we will discuss F&R before negation.
14:16:46 <ericP> LeeF: should we be using issue tracker or the wiki?
14:16:57 <kjetil_> q+ to say that HTTP RESTful is missing from the agenda too
14:17:12 <LukeWM> q+
14:17:14 <ericP> AxelPolleres: goal of the page is to aggregate e.g. update issues on the update page
14:17:17 <AndyS> Is the Update page supposed to have all the things w have discussed so far?
14:17:26 <AxelPolleres> ack Lee
14:17:26 <Zakim> LeeF, you wanted to ask about vis a vis
14:17:35 <kjetil_> ack me
14:17:37 <Zakim> kjetil_, you wanted to say that HTTP RESTful is missing from the agenda too
14:17:40 <LeeF> ACTION: Lee to create (& link) tracked issues for everything listed at
14:17:40 <trackbot> Created ACTION-70 - Create (& link) tracked issues for everything listed at [on Lee Feigenbaum - due 2009-08-04].
14:17:59 <ericP> kjetil: would like HTTP ReSTful update on the agenda today
14:18:23 <ericP> AxelPolleres: wanted to start with issues we've already discussed. happy to get to [HTTP ReSTful update]
14:18:55 <ericP> kjetil, update is high-level discussion -- would like that before detailed discussion
14:19:15 <ericP> kjetil: update is high-level discussion -- would like that before detailed discussion
14:19:29 <ericP> ... would like a straw poll
14:19:39 <LeeF> can someone explain to me what the high-level discussion is that's different from what we'd already resolved?
14:19:44 <AxelPolleres> q?
14:19:46 <Zakim> -LukeWM
14:19:50 <kjetil_> Zakim, mute me
14:19:50 <Zakim> kjetil_ should now be muted
14:19:51 <ericP> AxelPolleres: will put ReSTful update on next agenda
14:20:10 <AxelPolleres> topic: Establish task-forces for some time-permitting features
14:20:37 <kjetil_> LeeF, have we resolved anything regarding HTTP REST Update?
14:20:47 <Zakim> +??P19
14:20:49 <LeeF> kjetil, yes, we resolved to pursue them wherever they make sense
14:21:05 <ericP> AxelPolleres: while we need to spend telecon time on required features, we don't want to forget time-permitting
14:21:16 <LukeWM> zakim, ??P19 is me
14:21:16 <Zakim> +LukeWM; got it
14:21:28 <ericP> ... would like to find task forces which will meet at other times
14:21:58 <ericP> ... need one or two folks to drive these issues
14:22:06 <LeeF> kjetil, back on June 2 - see
14:22:06 <ericP> ... would like poll progress in a month
14:22:10 <LukeWM> AndyS, I think that the update issues discussed so far ought to be on the wikipage, but no one has added anything apart from me as far as I can tell.
14:22:19 <AxelPolleres> q?
14:22:32 <bglimm> I am volunteering for other entailment regimes
14:22:54 <AndyS> I see a lot of things :: "Negation" and "Time Permitting Features" 
14:22:58 <ericP> LukeWM: update wiki page doesn't cover all issues -- encourage group to flush it out
14:23:12 <kjetil_> LeeF, we're sidetracking here, but after that, there has come up four concrete alternatives to pursue, some of which are very different
14:23:25 <ericP> AxelPolleres: think that's covered with LeeF's action to transfer issues list issues to update wiki page
14:23:33 <LeeF> kjetil, ok, that's what i was asking about, since i've been out of the loop for a couple of weeks
14:23:40 <kjetil_> LeeF, for example, I and SimonS have forwarded diametrically different proposals
14:23:46 <AxelPolleres> BGP extensions for entailment regimes
14:23:55 <AxelPolleres>
14:24:04 <ericP> AxelPolleres: for BGP entailment regimes, had 5 folks interested
14:24:43 <ericP> ... Birte and Bijan available to lead Entailment Regime TF
14:25:33 <ericP> ... expect a report in a month to provide info for F&R doc
14:26:00 <AxelPolleres> LeeF: suggests strawpoll per feature.
14:26:21 <AndyS> I am interested in BGP entailment regimes (to implement some of them)
14:26:30 <AxelPolleres> strawpoll: who wants to contribute to BGP entailment TF? 
14:26:40 <bglimm> +1
14:26:40 <ivanh> I am interested by the BGP one
14:26:45 <AxelPolleres> (+1 means yes, -1 no)
14:26:48 <AxelPolleres> +1
14:26:48 <ivanh> +1
14:26:52 <kjetil_> -1
14:26:57 <LukeWM> -1
14:27:10 <SimonS> -1
14:27:13 <kasei> -1
14:27:13 <AndyS> +1
14:27:26 <SimonKJ> -1
14:27:44 <ericP> -ei^2
14:27:44 <pgearon> +1
14:28:25 <AxelPolleres>  Feature: PropertyPaths
14:28:31 <AxelPolleres>
14:28:59 <kjetil_> Zakim, unmute me
14:28:59 <Zakim> kjetil_ should no longer be muted
14:29:27 <AxelPolleres> AndyS takes lead on PropPaths
14:29:31 <ericP> AndyS: i will drive the PropertyPaths TF
14:30:07 <kjetil_> Zakim, mute me
14:30:07 <Zakim> kjetil_ should now be muted
14:30:13 <ericP> kjetil: I expect to provide test cases for PropertyPaths
14:30:29 <LukeWM> +1
14:30:30 <AlexPassant> +1
14:30:30 <SimonKJ> +1
14:30:30 <ivanh> +1
14:30:32 <LeeF> +1
14:30:39 <pgearon> +1
14:31:07 <kjetil_> +1
14:31:17 <AxelPolleres> +0
14:31:32 <SimonS> +0
14:32:13 <AxelPolleres>  Feature: Commonly used SPARQL functions 
14:32:18 <ericP> LeeF: it would be great if the TFs meet
14:32:54 <ericP> ericP: TFs can "/invite Zakim #sparql" and "Zakim, space for 5?" to get an ad-hoc conference
14:34:02 <AxelPolleres> Eric: feature function library I could provide input there.
14:34:14 <ericP> LeeF: this one will be easier so doesn't need so much formalism
14:34:27 <ericP> AxelPolleres: would like someone responsible
14:34:51 <AxelPolleres> Axel: I will kick off function library discussion
14:35:32 <AxelPolleres> ericP: existing functions and operators table provides a good way to extend the core.
14:36:02 <AxelPolleres> AndyS: rather identifying URIs for common functions.
14:36:39 <AxelPolleres> strawpoll: who to contribute in function library?
14:36:41 <AxelPolleres> +1
14:37:04 <AxelPolleres>
14:37:32 <AxelPolleres>  feature: federated query
14:37:33 <ericP> AxelPolleres: champions AndyS, iv_an_ru, SimonS
14:37:51 <ericP> ... TF lead: SimonS 
14:37:54 <kjetil_> +1 (hopes to contribute test cases again)
14:37:56 <ericP> +1
14:37:58 <pgearon> +!
14:38:00 <SimonKJ> +1
14:38:00 <pgearon> +1
14:38:02 <kasei> +1
14:38:10 <LeeF> I hope to contribute, but not sure I'll have enough time
14:38:31 <AndyS> as for LeeF
14:38:39 <AxelPolleres> q?
14:38:48 <LeeF> ack LukeWM
14:38:48 <AxelPolleres> ack LukeWM
14:39:00 <ericP> AxelPolleres: we have folks assigned to all features, please go ahead and start your task forces
14:39:12 <AxelPolleres> topic: minus vs. unsaid
14:39:37 <AxelPolleres> topic: F&R document
14:39:40 <kjetil_> Zakim, unmute me
14:39:40 <Zakim> kjetil_ should no longer be muted
14:40:02 <ericP> kjetil: F&R FPWD published
14:40:21 <ericP> ... my time is uncertain
14:40:36 <ericP> ... have inserted tempates for time-permitting features
14:40:46 <ericP> ... need to get them into shape
14:41:00 <ericP> AlexPassant: will have time in Aug
14:41:41 <ericP> AxelPolleres: need to get ahold of time-permitting TF leads to get paragraphs
14:41:43 <LukeWM> LukeWM has joined #sparql
14:42:21 <ericP> ... would like next F&R at same time as FPWDs of Query and Update
14:43:24 <ericP> ericP: would be nice to give time to get public feedback, but not sure that's feasible given the timeline
14:43:34 <ericP> AxelPolleres: do we need more advertising?
14:43:47 <kjetil_> freetext has been brought up
14:43:56 <ericP> kjetil: swig?
14:44:02 <kjetil_> has it been posted to the semantic-web ml?
14:44:12 <kjetil_> it has been chumped on #swig
14:44:22 <ericP> AxelPolleres: please suggest publication locations
14:44:30 <ericP> ... we should contact liased WGs
14:44:57 <AxelPolleres> ACTION: Axel to re-check where to announce F&R (e.g. liaisons)
14:44:58 <trackbot> Created ACTION-71 - Re-check where to announce F&R (e.g. liaisons) [on Axel Polleres - due 2009-08-04].
14:44:59 <ericP> AndyS: when's last F&R, last call [for Query and Update]?
14:45:09 <ericP> ivanh: it's a note, so we decide the process
14:45:40 <ericP> kjetil: would like to make a wiki page copying the F&R doc so folks can edit it
14:45:58 <AxelPolleres> ACTION: Alex to take F&R current version back to wiki for editing
14:45:58 <trackbot> Created ACTION-72 - Take F&R current version back to wiki for editing [on Alexandre Passant - due 2009-08-04].
14:46:38 <AxelPolleres> topic: MINUS vs. UNSAID
14:47:15 <ericP> LeeF: AndyS written up UNSAID and ericP's written MINUS
14:47:23 <kjetil_> probably a good idea to create new pages rather than use the Category:Features pages
14:47:28 <kjetil_> Zakim, mute me
14:47:28 <Zakim> kjetil_ should now be muted
14:47:33 <ericP> ... from implementor's perspectice, MINUS is an algebraic op to combine result sets
14:47:58 <ericP> ... while UNSAID is a FILTER which takes a triple pattern and examines existing bindings
14:48:29 <ericP> ... from query writer's perspective, in most cases MINUS and UNSAID give you the same results
14:48:53 <ericP> ... when they don't it's when OPTIONALs introduce vars
14:49:06 <ericP> ... those queries tend to be strage and artificial
14:49:32 <AxelPolleres>  BTW: I will assign actions to the TF leads to kick-off discussions, just to keep track.
14:49:44 <LukeWM> q+
14:49:45 <ericP> ... someone listed a use case, examining where it is more natural to express one way or another
14:50:09 <LeeF> ack LukeWM
14:50:26 <ericP> LukeWM: if we banned opts, would it make MINUS and UNSAID equivalent?
14:50:44 <ericP> LeeF: i think we think they're identical at that point
14:51:03 <ericP> LukeWM: just wondering if there are compelling use cases for OPTIONALs
14:51:15 <kasei> i'm not sure it can be identical if we haven't nailed down the antijoin(+restriction) issue that ericP was discussing on the list yesterday.
14:51:26 <AxelPolleres> q+ on  OPTIONALs
14:51:39 <LeeF> ack AxelPolleres
14:51:39 <Zakim> AxelPolleres, you wanted to comment on OPTIONALs
14:51:57 <ericP> LeeF: proposal to prohibit OPTIONALs in the unsaid pattern is interesting
14:52:13 <LeeF> kasei, you're right, but i've been working on the assumption that we are dealing with AntiJoin+Restriction, which is the same semantics as UNSAID for the cases in which the two patterns share no variables I think
14:52:29 <ericP> AxelPolleres: i think restricting patterns makes it harder
14:52:29 <ericP> +1
14:52:35 <AxelPolleres> ack Axel
14:52:37 <pgearon> +q
14:52:42 <LeeF> ack pgearon
14:52:56 <AndyS> Messy syntax but that's all, I think.
14:53:40 <ericP> pgearon: leaning towards eliminating OPTIONALs because you don't want to eliminiate solutions which would have !BOUND vars
14:53:54 <SimonS> +1 pgearon.
14:53:55 <AxelPolleres> if we disallow that, then we probably should equally think about forbidding nesting optionals... ?!?
14:54:13 <ericP> LeeF: who's uncomfortable with prohibiting OPTIONALs in MINUS?
14:54:14 <ericP> +1
14:54:56 <AxelPolleres> +1 to eric's +1 ;-)
14:55:07 <kasei> for the unsaid version, I think it makes a lot of sense, since I believe optional is a no-op in that case. not sure about minus.
14:55:09 <AndyS> Unsure about this because optionals appear in the LHS so the compatibility rules seem odd.
14:55:38 <SimonKJ> Could go either way on this, there's complexity in both choices
14:56:09 <ericP> ericP: would rather the discomfort occur when folks have to understand what happens with unbound vars rather than have different rules for subtraction sets
14:56:21 <AxelPolleres> LeeF: as long as the semantics is clear, for the corner cases, I think we don't have to worry too much about corner cases arising from OPTIONAL use
14:56:30 <AxelPolleres> (hope that summarizes lee right)
14:57:04 <ericP> Leef: MINUS (modulo ignoring empty results), UNSAID, OPTIONAL prohibited
14:57:22 <pgearon> we *could* say that OPTIONAL on the right is undefined. Is that a terrible idea if there is no use case to use it?
14:57:42 <LeeF> MINUS-AntiJoin+Restriction
14:57:44 <LukeWM> +1
14:57:47 <ericP> +1
14:57:48 <AndyS> -1
14:57:53 <SimonKJ> -1
14:57:54 <SimonS> -1
14:57:55 <ivanh> 0
14:57:56 <AxelPolleres> 0
14:58:00 <LeeF> +1
14:58:01 <kjetil_> 0
14:58:02 <AlexPassant> 0
14:58:11 <bglimm> 0
14:58:11 <kasei> i don't want to drag things down here, but i'm still shaky on the equivalence of unsaid and the antijoin+restriction...
14:58:12 <Prateek> 0
14:58:17 <kasei> -1
14:58:50 <kasei> maybe I need to re-read the emails
14:58:58 <LeeF> UNSAID 
14:58:59 <ericP> why do they have to be equiv?
14:59:05 <ericP> 0
14:59:08 <AndyS> +1
14:59:09 <kasei> +1
14:59:10 <AlexPassant> +1
14:59:11 <LukeWM> -1
14:59:11 <ivanh> +1
14:59:11 <AxelPolleres> +1
14:59:12 <SimonKJ> +1
14:59:12 <SimonS> +1
14:59:14 <LeeF> +1
14:59:20 <Prateek> +1
14:59:28 <kasei> ericP: they don't but I thought that had been asserted for the case without optionals (perhaps I've misuderstood that, too, though :)
14:59:33 <pgearon> abstain on both
14:59:48 <pgearon> probably for similar reasons to LeeF
14:59:53 <LeeF> MINUS or UNSAID prohibiting OPTIONALs on the RHS
14:59:59 <ericP> -1
15:00:04 <kjetil_> 0
15:00:07 <kasei> +1
15:00:10 <AndyS> -1
15:00:10 <SimonS> 0
15:00:12 <SimonKJ> 0
15:00:16 <LukeWM> +1 
15:00:18 <AxelPolleres> 0 (not entirely egainst it, since it seems it might drop worst case complexity)
15:00:19 <ivanh> 0 (does not know yet...)
15:00:22 <Prateek> 0
15:00:25 <LeeF> -1
15:00:30 <bglimm> 0
15:00:41 <kasei> although I think this might be two different things depending on UNSAID or MINUS
15:00:51 <pgearon> I'd rather "undefine" this pattern, rather than prohibit it
15:02:12 <LukeWM> AndyS, sure
15:02:37 <ericP> LeeF: clear leaning towards UNSAID
15:02:44 <AxelPolleres> LeeF/Eric: at least in FPWD we should sketch both.
15:02:46 <ericP> ... consistent with having AndyS edit the template
15:03:05 <ericP> ... plus red spec text inclusing alternatives
15:03:56 <ericP> topic: wrap-up
15:04:13 <ericP> AxelPolleres: i'll make actions for TF leads
15:04:30 <ericP> ... action to get TF leads to kick off discussion
15:04:30 <AxelPolleres> Adjourned.