IRC log of dawg on 2005-09-20

Timestamps are in UTC.

14:28:13 [RRSAgent]
RRSAgent has joined #dawg
14:28:13 [RRSAgent]
logging to http://www.w3.org/2005/09/20-dawg-irc
14:28:19 [ericP]
zakim, this will be dawg
14:28:19 [Zakim]
ok, ericP, I see SW_DAWG()10:30AM already started
14:28:28 [ericP]
RRSAgent, pointer?
14:28:28 [RRSAgent]
See http://www.w3.org/2005/09/20-dawg-irc#T14-28-28
14:28:33 [ericP]
zakim, who is here?
14:28:33 [Zakim]
On the phone I see PatH
14:28:34 [Zakim]
On IRC I see RRSAgent, Zakim, patH, franconi, LeeF, AndyS, jeen, SerT, SteveH, afs, DanC, ericP
14:28:42 [ericP]
Meeting: DAWG
14:29:27 [Zakim]
+??P18
14:29:30 [ericP]
Chair: PatH
14:29:37 [ericP]
Scribe: SteveH
14:29:38 [Zakim]
+[IBMCambridge]
14:29:49 [ericP]
Time: 14:30Z
14:29:50 [LeeF]
Zakim, [IBMCambridge] is LeeF
14:29:50 [Zakim]
+LeeF; got it
14:30:05 [jeen]
Zakim, ??P18 is JeenB
14:30:05 [Zakim]
+JeenB; got it
14:30:08 [Zakim]
+Ericp
14:30:11 [Yoshio]
Yoshio has joined #dawg
14:30:52 [Zakim]
+??P9
14:30:55 [AndyS]
zakim, ??P9 is AndyS
14:30:55 [Zakim]
+AndyS; got it
14:31:14 [AndyS]
zakim, who is on the phone?
14:31:14 [Zakim]
On the phone I see PatH, JeenB, LeeF, Ericp, AndyS
14:31:16 [Zakim]
+Yoshio
14:31:17 [kendall]
kendall has joined #dawg
14:31:36 [Zakim]
+??P8
14:32:03 [Zakim]
+Kendall_Clark
14:32:35 [ericP]
zakim, ??P8 is Souri
14:32:35 [Zakim]
+Souri; got it
14:34:06 [Zakim]
+Ernesto_Damiani
14:34:07 [kendall]
Btw, I'm empowered to say (:>) that Bijan will be here shortly; he had a dr's appointment thing to take care of.
14:34:19 [AndyS]
All : Please join the phone telecon.
14:34:35 [AndyS]
That is where we will be discussing this material.
14:34:51 [Zakim]
+NickG
14:35:02 [SteveH]
Zakim, NickG is SteveH
14:35:02 [Zakim]
+SteveH; got it
14:35:24 [JosD]
JosD has joined #dawg
14:35:53 [ericP]
zakim, Ernesto_Damiani is really Enrico_Franconi
14:35:53 [Zakim]
+Enrico_Franconi; got it
14:36:15 [Zakim]
+Jos_De_Roo
14:36:48 [kendall]
Let's hope the real (if there are such) "Voices from Above" are more helpful, coherent, and friendly. :>
14:39:34 [kendall]
excuse me
14:39:52 [kendall]
franconi: the intent is to give a formal semantics for SPARQL as-is
14:40:04 [ericP]
Erico: posted a semantics that are intened to be consistent wiht the spirit of SPARQL and resolving the subgraph vs. entailment debate
14:40:18 [jeen]
http://lists.w3.org/Archives/Public/public-rdf-dawg/2005JulSep/0450.html
14:40:26 [Yoshio]
s/Erico/Enrico/
14:40:28 [Zakim]
+ +44.797.160.aaaa
14:41:11 [ericP]
zakim, aaaa is Ian_Horrocks
14:41:11 [Zakim]
+Ian_Horrocks; got it
14:41:17 [ericP]
SP?
14:41:47 [LeeF]
I'm hearing a lot of noise on the call.
14:41:49 [kendall]
hmm, can we mute Ian?
14:42:03 [Zakim]
+[UMD]
14:42:06 [ericP]
zakim, please mute Ian_Horrocks
14:42:06 [Zakim]
Ian_Horrocks should now be muted
14:42:14 [ericP]
Bijan, i presume?
14:42:21 [kendall]
yes, I assume so
14:42:35 [bijan]
bijan has joined #dawg
14:42:49 [ericP]
zakim, UMD is Bijan
14:42:49 [Zakim]
+Bijan; got it
14:43:16 [ericP]
zakim, please unmute Ian_Horrocks
14:43:16 [Zakim]
Ian_Horrocks should no longer be muted
14:43:18 [kendall]
hmm, yes, someone should at least tell Ian that he's muted
14:43:41 [LeeF]
*6 i believe
14:43:58 [LeeF]
Maybenot :)
14:44:15 [ericP]
zakim, please mute Ian_Horrocks
14:44:15 [Zakim]
Ian_Horrocks should now be muted
14:45:45 [ericP]
SteveH, if you hear anything you'd like in the record, you're listed as scribe
14:46:02 [SteveH]
ericP, yeah, I cant think and type though :-/
14:46:12 [kendall]
I'm trying to scribe, since I can't think anyway. :>
14:46:17 [ericP]
also, things you particularly don't want in the record, they're probably relevent too
14:46:27 [SteveH]
moreso i suspect
14:47:14 [ericP]
Enrico:
14:47:16 [ericP]
match only URIs and literals
14:47:33 [SteveH]
franconi, skolemise bNodes by replacing with newly minted bNodes gets you the semantics we have now (?)
14:47:34 [ericP]
skolemize bNodes into URIs
14:47:44 [AndyS]
Skolomise bNodes, do entailment (no bNodes), deskolomize
14:47:54 [ericP]
and convert them to bNodes [upon reporting?]
14:48:00 [ericP]
.
14:48:21 [AndyS]
Is this the same as saying 1/ no shared bNodes and 2/ only bnodes from the original graph in solutions?
14:49:58 [bijan]
zakim, q+
14:49:58 [Zakim]
I see bijan on the speaker queue
14:50:37 [SteveH]
franconi: SPARQL can be represented by an algebra (like SQL)
14:52:02 [kendall]
bijan: I'd like to have a calculus for all of SPARQL. But we don't have that, and that's not what Enrico has proposed.
14:53:09 [ericP]
q?
14:53:12 [ericP]
ack bijan
14:53:58 [ericP]
zakim, please unmute Ian_Horrocks
14:53:58 [Zakim]
Ian_Horrocks should no longer be muted
14:54:27 [ericP]
zakim, please mute Ian_Horrocks
14:54:27 [Zakim]
Ian_Horrocks should now be muted
14:57:49 [kendall]
franconi: our proposal doesn't include CONSTRUCT semantics
14:58:04 [AndyS]
Enrico: CONSTRUCT is analogous to object construction in SQL
14:58:26 [AndyS]
Enrico: this is not covered by my proposal
15:02:24 [SteveH]
franconi: two equivalent graphs may give different answers (lean v's fatty)
15:02:46 [AndyS]
q+
15:03:30 [SteveH]
franconi: if we add a minimisation step to skolemise, unskolemise then we get same results
15:04:51 [SteveH]
franconi: minimisation is expensive, so should be optional
15:05:08 [SteveH]
(NP hard (?) in worst case)
15:06:04 [AndyS]
I'm unclear as to NP-hard WRT what? The queried data or the result set only.
15:06:16 [SteveH]
franconi: minimisation is only neccesary where there are bNodes in the data
15:06:54 [ericP]
i guess graph match is NP-hard. seems it would be that NP prob, but i can't quite see where it applies
15:07:33 [LeeF]
AndyS: If I understand Enrico correctly, the minimisation can occur outside of the graph matching, on the result set only, which would mean it's NP-Hard in the size of the result set. But, I give no guarantees that I understand any of this correctly. :-/
15:07:35 [SerT]
u can see minimisation as conjunctive query containment
15:07:50 [bijan]
zakim, q+
15:07:50 [Zakim]
I see AndyS, bijan on the speaker queue
15:08:51 [bijan]
zakim, q-
15:08:51 [Zakim]
I see AndyS on the speaker queue
15:09:03 [AndyS]
LeeF: I hope that is true but somethign said didn't back that up. It seems to be equiv to entailment WRT the data.
15:09:38 [bijan]
zakim, q+ to say that there are two issues: 1) the specification of the correct answers to a query given a semantics and 2) how, in the language or protocol, which semantics are desired or in force
15:09:38 [Zakim]
I see AndyS, bijan on the speaker queue
15:09:53 [JosD]
q+
15:10:37 [AndyS]
q+ to say that it might be a feature of the service - not a client option.
15:11:02 [ericP]
agh!
15:11:21 [ericP]
ack AndyS
15:11:21 [Zakim]
AndyS, you wanted to say that it might be a feature of the service - not a client option.
15:11:42 [SerT]
result set
15:11:45 [SteveH]
AndyS: the mini. alg. NPH w.r.t what? result set or KB size
15:12:02 [ericP]
q+ Ian_Horrocks a reminder to poll him
15:12:03 [SteveH]
franconi: w.r.t. coreferent nodes
15:12:10 [LeeF]
franconi: NP-hard WRT to coreferenced nodes
15:12:12 [ericP]
q+ Ian_Horrocks to say a reminder to poll him
15:12:52 [SteveH]
coreferent variables
15:14:04 [Zakim]
-Ian_Horrocks
15:14:19 [ericP]
q-Ian_Horrocks
15:14:48 [patH]
Ian, got that.
15:15:34 [ericP]
ack bijan
15:15:34 [Zakim]
bijan, you wanted to say that there are two issues: 1) the specification of the correct answers to a query given a semantics and 2) how, in the language or protocol, which
15:15:37 [Zakim]
... semantics are desired or in force
15:15:40 [ericP]
ack JoseD
15:15:46 [ericP]
ack JosD
15:16:23 [SteveH]
JosD: suppose we have <A> <B> _:C . _:A _:B _:C
15:16:40 [ericP]
JosD: <a> <b> _:c minimizes to _:a _:b _:c ?
15:16:56 [kendall]
zakim, mute me
15:16:56 [Zakim]
Kendall_Clark should now be muted
15:17:07 [ericP]
Enrico: this minimizes to <a> <b> _:c
15:17:12 [JosD]
<A> <B> _:C . _:A <B> <C>
15:17:55 [ericP]
Enrico: this [above] is already minimized
15:18:49 [SerT]
minimisation interacts with FILTER
15:19:05 [ericP]
explain?
15:19:20 [bijan]
q+
15:19:21 [SteveH]
FILTER(bNode(?a))?
15:19:41 [SerT]
u can filter out tuples on the basis of blank nodes
15:20:07 [SerT]
so FILTER can throw away ground tuples
15:20:20 [SerT]
yep
15:20:22 [AndyS]
q+
15:20:27 [ericP]
tx
15:20:38 [ericP]
ack bijan
15:20:56 [ericP]
ack AndyS
15:21:51 [ericP]
PatH: i think we want a flag in the query to say "i want a minimal solutin"
15:22:04 [ericP]
Enrico: this is "distinct" in SQL
15:22:09 [SteveH]
franconi: its equivalent to SQLs DISTINCT
15:22:25 [SteveH]
I dont see how its related to SQLs DISTINCT
15:22:28 [ericP]
... UNION may add redundancy
15:22:42 [AndyS]
It's more expensive than DISTINCT because DISTINCT is streamable
15:22:56 [ericP]
... same with sub select [did i get that right?]
15:23:38 [AndyS]
Yes - I think it is the same
15:23:41 [bijan]
AndyS...that's an interesting point
15:23:49 [bijan]
q+
15:24:03 [kendall]
hmm, in my ample personal experience (alas), Enrico is nothing like a fundamentalist Christian. :>
15:26:56 [AndyS]
zakm, ack bijan
15:27:01 [AndyS]
zakim, ack bijan
15:27:01 [Zakim]
I see no one on the speaker queue
15:27:31 [ericP]
q+ to ask why if this entailment parameter could be put in the service or the graph
15:30:43 [jeen]
q+ to say that not handling OWL explicitly is not the same as blocking possible OWL-enabling
15:32:28 [franconi]
q+
15:32:37 [jeen]
q-
15:32:47 [ericP]
http://www.w3.org/2003/12/swa/dawg-charter#derivedGraphs [[
15:32:49 [ericP]
The working group must recognize that RDF graphs are often constructed by aggregation from multiple sources and through logical inference, and that sometimes the graphs are never materialized. Such graphs may be arbitrarily large or infinite.
15:32:53 [ericP]
]]
15:33:57 [AndyS]
I'd point out "never materialized" in the talk of infinite graphs and inf closures
15:34:01 [AndyS]
zkim, ack EricP
15:34:04 [AndyS]
zakim, ack EricP
15:34:04 [Zakim]
ericP, you wanted to ask why if this entailment parameter could be put in the service or the graph
15:34:07 [Zakim]
I see franconi on the speaker queue
15:34:08 [jeen]
no prob, you said it better than I could :)
15:34:47 [SteveH]
bijan, and thanks for waving the RDFS flag :)
15:34:57 [bijan]
no problem
15:35:56 [AndyS]
eric: is making the entailement level a feature of the service acceptable to Bijan and Enrico?
15:36:03 [AndyS]
Bjian, Enrico: Yes
15:36:17 [AndyS]
Bijan: must stil define the outcome of various entailment levels
15:42:41 [franconi]
q-
15:43:05 [IanH]
IanH has joined #dawg
15:44:12 [IanH]
Sorry I dropped off the call - ran out of battery.
15:44:26 [patH]
we forgive you.
15:45:43 [kendall]
zakim, unmute me
15:45:43 [Zakim]
Kendall_Clark should no longer be muted
15:46:02 [AndyS]
Bijan: how to move forward?
15:47:10 [kendall]
Test cases needed
15:47:18 [AndyS]
Use cases and test cases would useful.
15:48:18 [kendall]
Everyone agrees that SPARQL should not be req'd to respect RDF entailment.
15:48:26 [kendall]
(is that correct scribing?)
15:48:39 [LeeF]
kendall: yes
15:48:49 [kendall]
seems worth recording right :>
15:48:55 [AndyS]
Yes.
15:49:09 [bijan]
Everyone also agrees that SPARQL should be *able* to respect RDF entailmetn :)
15:49:11 [bijan]
?
15:49:12 [SteveH]
and sometimes celebrating
15:49:59 [AndyS]
"should" yes - "must" (i.e. every impl must provide that mode) then, no
15:50:22 [bijan]
I.e., SPARQL should specify what the correct result sets are wrt to both "no" entailment and rdf entailment (and presuambly simple entailment)
15:50:24 [LeeF]
patH (?) consider the query: Do there exist any rdfs:ContainerMembershipProperty's against an empty graph - services should not be required to give any answers to that, even though logically they should
15:50:46 [AndyS]
Bijan - agree
15:51:39 [jeen]
bijan, "specify"? wouldn't simply referring to relevant parts of RDF Semantics be enough?
15:51:51 [bijan]
jeen, no, because of things like minimality
15:52:41 [AndyS]
Enrico: URL of service extended to include the minimalization mode
15:52:49 [bijan]
I.e., if you say "subgraph of the rdfization of the dedeuctive closure", different implementation can give different answers depending on how it regards redundancy in the answers
15:52:54 [AndyS]
Ian? Anythign to say?
15:52:54 [LeeF]
zakim, who's on the phone?
15:52:54 [Zakim]
On the phone I see PatH, JeenB, LeeF, Ericp, AndyS, Yoshio, Souri, Kendall_Clark, Enrico_Franconi, SteveH, Jos_De_Roo, Bijan
15:53:37 [IanH]
I missed a lot of the discussion, but what Enrico and Bijan are proposing sounds reasonable.
15:53:39 [kendall]
Who's gonna break the bad news to Connolly?! :>
15:53:48 [AndyS]
"bad"?
15:54:00 [kendall]
precisely
15:54:12 [AndyS]
We have a way forward - not a blockage
15:55:22 [kendall]
boo hiss
15:55:26 [kendall]
static on the line
15:55:46 [Zakim]
-JeenB
15:56:29 [ericP]
jeen, that's ok, we'd just gotten to the hippi love fest
15:56:41 [jeen]
oh boo, I missed the group hug :(
15:57:27 [LeeF]
q+ to ask if we have agreed one way or the other on whether this will affect the protocol (clients specifyoing desired entailment)
15:57:59 [kendall]
well, i want to know if we *have* to. that didn't seem clear.
15:58:22 [LeeF]
Right, that as well.
15:58:36 [kendall]
:>
15:58:45 [ericP]
AndyS, what would be helpful is a list of the things that change and what doesn't. we've had a good discussion today. we need to log that discussion
16:00:05 [ericP]
ACTION Bijon: take a pass through the editor's draft, listing what will change with the new semantics understanding, and what will not
16:00:11 [ericP]
ACTION Enrico: take a pass through the editor's draft, listing what will change with the new semantics understanding, and what will not
16:00:14 [kendall]
zakim, mute me
16:00:14 [Zakim]
Kendall_Clark should now be muted
16:00:32 [LeeF]
s/Bijon/Bijan
16:00:33 [IanH]
Who is this Bijon dude?
16:00:49 [ericP]
ACTION Bijan: take a pass through the editor's draft, listing what will change with the new semantics understanding, and what will not
16:00:53 [ericP]
action -1
16:01:08 [bijan]
Who's this Bijon person?
16:01:23 [jeen]
your good twin?
16:01:26 [patH]
Action Pat to summarize the consensus.
16:01:36 [kendall]
I've been asked many times to leave conference talks because I was typing too loud!
16:01:42 [AndyS]
One procedural thing - we are having a meeting next week (27/Sept) aren't we? Hint, hint
16:01:44 [kendall]
I feel (or hear?) Pat's pain
16:01:55 [ericP]
ACTION Pat: summarize the entailment consensus
16:02:20 [kendall]
I'll scribe
16:02:31 [AndyS]
Thx Kendall for offerig to scribe
16:02:42 [kendall]
I have to go 2 minutes ago. Ciao!
16:02:48 [Zakim]
-Souri
16:02:50 [Zakim]
-Jos_De_Roo
16:02:52 [Zakim]
-SteveH
16:02:54 [Zakim]
-Kendall_Clark
16:03:02 [ericP]
next meeting: next week, chair: DanC or ericP, scribe: KendallC
16:03:02 [Zakim]
-Yoshio
16:03:09 [LeeF]
q-
16:03:37 [ericP]
ADJOURN
16:03:53 [AndyS]
Andy asks about whether skolomisation of bNodes and equiv to restricting to told facts.
16:03:59 [ericP]
rrsagent, please draft minutes
16:03:59 [RRSAgent]
I have made the request to generate http://www.w3.org/2005/09/20-dawg-minutes.html ericP
16:04:09 [ericP]
rrsagent, please make minutes world-readable
16:04:09 [RRSAgent]
I'm logging. I don't understand 'please make minutes world-readable', ericP. Try /msg RRSAgent help
16:04:12 [ericP]
rrsagent, please make minutes world readable
16:04:12 [RRSAgent]
I'm logging. I don't understand 'please make minutes world readable', ericP. Try /msg RRSAgent help
16:04:17 [AndyS]
It is confirmed.
16:05:28 [ericP]
zakim, please leave us
16:05:28 [Zakim]
I don't understand 'please leave us', ericP
16:05:34 [ericP]
zakim, bye
16:05:34 [Zakim]
leaving. As of this point the attendees were PatH, LeeF, JeenB, Ericp, AndyS, Yoshio, Kendall_Clark, Souri, SteveH, Enrico_Franconi, Jos_De_Roo, +44.797.160.aaaa, Ian_Horrocks,
16:05:34 [Zakim]
Zakim has left #dawg
16:05:37 [Zakim]
... Bijan
16:05:44 [ericP]
rrsagent, bye
16:05:44 [RRSAgent]
I see 3 open action items saved in http://www.w3.org/2005/09/20-dawg-actions.rdf :
16:05:44 [RRSAgent]
ACTION: Enrico to take a pass through the editor's draft, listing what will change with the new semantics understanding, and what will not [2]
16:05:44 [RRSAgent]
recorded in http://www.w3.org/2005/09/20-dawg-irc#T16-00-11
16:05:44 [RRSAgent]
ACTION: Bijan to take a pass through the editor's draft, listing what will change with the new semantics understanding, and what will not [3]
16:05:44 [RRSAgent]
recorded in http://www.w3.org/2005/09/20-dawg-irc#T16-00-49
16:05:44 [RRSAgent]
ACTION: Pat to summarize the entailment consensus [4]
16:05:44 [RRSAgent]
recorded in http://www.w3.org/2005/09/20-dawg-irc#T16-01-55