12:55:14 RRSAgent has joined #awwsw 12:55:14 logging to http://www.w3.org/2009/03/31-awwsw-irc 12:55:19 Zakim has joined #awwsw 12:55:25 zakim, this will be awwsw 12:55:25 ok, dbooth; I see TAG_(AWWSW)9:00AM scheduled to start in 5 minutes 12:56:04 Meeting: AWWSW 12:56:09 Chair: Jonathan Rees (jar) 13:00:16 TAG_(AWWSW)9:00AM has now started 13:00:23 +DBooth 13:02:16 rrsagent, make logs public 13:09:20 +TimBL 13:13:49 +jar 13:15:06 jar has joined #awwsw 13:17:51 Topic: GenericResource 13:17:52 http://www.w3.org/DesignIssues/Generic.html 13:21:04 dbooth: GR doesn't seem to capture which represetnations are captured, but REST and ftrr:IR do. 13:21:09 timbl: Generic resource puts constraints on representations 13:22:13 timbl has joined #awwsw 13:22:21 if X u:isRepresentationOf G, and r is a representation of X, then r is a representation of G 13:22:39 (X is a u:FixedResource) 13:23:31 timbl: I should probably fix [the dual use of the word 'representation' to mean fixed resource vs. REST representation] 13:24:34 timbl: representation invariant = always the same mime type 13:25:43 dbooth: there are three axes: mime type, language, and time. 13:26:32 jar: so fixed = invariant along all three axes 13:27:09 jar: Sorry, mistake in the above I think (u:isRepresentationOf etc) 13:27:53 timbl: Should rename 'representation invariant' to 'content-type invariant' 13:28:22 dbooth: So GR has three axes, but it looks like the names used on the third axis (the content type access) should be changed from "Representation" to "ContentType". 13:29:22 http://www.w3.org/2006/gen/ont 13:29:24 jar: I was looking for a property that is the conjunction of all three properties - 'X is a fixed resource having as its sole representation one of the representations of G' 13:29:32 dbooth: So the axis should be called 'Content Type', the class should be 'ContentTypeInvariant' and the property should be called 'isContentTypeInvariantVersionOf'. 13:31:04 ... Also it looks like u:isVersionOf should be renamed u:isTimeInvariantVersionOf to be clearer also. 13:31:52 timbl: This metadata might be provided by a link header, for example. 13:32:27 timbl: this ontology (GR) would be found via, say, a Link: header and is meant to explain some particular resource 13:33:26 dbooth: Might also define a property u:isFixedVersionOf, which would be a subproperty of u:isTimeInVariantVersionOf, u:isLanguageInvariantVersionOf and u:isContentTypeInvariantVersionOf. 13:35:46 jar: OK, right now I don't care what it's called. isFixedVersionOf will do 13:36:08 jar: isTimeSpecificVersionOf ? 13:36:31 Oops, I shoudl have used hte word 'specific' instead of 'invariant', so the above should have been: 13:37:07 u:isTimeSpecificVersionOf, u:isLanguageSpecificVersionOf and u:isContentTypeSpecificVersionOf 13:37:36 isVersionOf = common superproperty 13:37:44 isFixedVersionOf = common subproperty 13:37:53 and finally, the conjunction of all three would be isFixedVersionOf. 13:42:09 timbl: but if you know that x isFixedResource of y, then are you saying that y *is* a GenericResource? What if it only has one language? 13:42:41 jar: So it's a subclass relation. 13:42:47 timbl: Yes, not a proper subclass. 13:43:15 fixed resource is a subclass of generic resource, right? 13:43:44 timbl: Yes. 13:44:02 timbl: Can't distinguish generic resource from information resource. 13:46:50 +Alan_Ruttenberg 13:47:13 alan, we're editing http://www.w3.org/DesignIssues/Generic.html 13:49:05 alan, http://www.w3.org/2006/gen/ont too 13:49:05 http://www.w3.org/2006/gen/ont 13:49:14 http://www.w3.org/2006/gen/ont.n3 13:51:03 jar: How do you determine if something is a representation of a generic resource? what's the truth criterion? 13:51:22 ... if you *have* a rep, how do you decide if it is a rep of a particular GR? 13:52:17 timbl: Then you have metadata and data. When you did a fetch . . . .? 13:52:24 jar: But what if you got it some other way? 13:52:51 ... I want to be able to prove that two URIs name different resources. In principle, what's the theoretical test you could make? 13:53:15 ... Eg for the bible, i could look at the rep and decide if its' a rep of the bible. 13:53:18 timbl: it's one of these open world things 13:53:44 timbl: Typically when you look at the front cover of a book, it says "this printing" and it says 'also available in these languages'. 13:54:35 timbl: Different nonoverlapping author lists might imply that things are different 13:54:49 timbl: You can tell that they're the same, but very difficult to prove different. Like if you have two people. Eg, if you have non-overlapping author/publication lists, then it's a different person, though sometime's there's a mistake. 13:55:26 jar: So it's a much less commital notion than the other models on the table, such as REST and David's ftrr:IR. 13:56:03 jar: The question is whether these models are overlapping, different, the same, etc. 13:56:27 ... David at the start of this call was asking how two of these in particular compare to each other. Need to explore the boundary cases to answer that. 13:57:09 timbl: Roy was happy to say that people are resources *and* have representations 13:57:22 timbl: Roy's REST was pre-SemWeb, so he was happy saying a rep is a rep of a person. Also happy saying a URI for a robot is for a control panel, and also a URI email addr that's used indirectly to identify a person. 13:57:47 jar: But we're only looking at documents here, and he did model documents. 13:58:43 timbl: 302 problem 13:58:47 timbl: I found a bug related to this stuff, it made some assumption from a 302 that threw it into a loop. 14:00:23 jar: Can user-agent affect (some agent's) choice of representation [in each model]? 14:00:39 jar: Another question: can user agent affect the choice of rep? 14:01:30 dbooth: Good question, because 2616 makes clear that conneg can use *anything* in the request to make a choice of rep, but that's not captured in this little GR ontology, which only captures axes of time, language and content type variation. 14:02:46 dbooth: This GR ontology captures three of the most important axes of variation, even if it does not capture all of the variation that 2616 permits. 14:03:08 timbl: One possibility is to say that there are other axes beyond these three 14:03:39 timbl: We still need 3 axes. If you say this is a FixedResource, its independent of not only these three axes, but also all other axes. I kinda like that. 14:04:14 ... So if someone has geographic location of the user, we could add that as another dimension, and FixedResource would have the same meaning. 14:05:48 timbl: Not going to have the ontology in two places (the generic resources design issues document, and the ont RDF file) 14:05:52 alan, can't hear you 14:07:03 -Alan_Ruttenberg 14:08:33 jar: For every 200-responding thing, there is an IR, right? Wondering if GRs are meant to be idealized. 14:09:02 jar: Which comes first, the web page, or the generic resource? 14:09:31 timbl: Some generic resources are not on the web, some are. 14:10:03 timbl: For lots of things like wikipedia pages, that page *is* the IR. For other things, there is a work, like a paper is published in multiple places, and they're the same work, whethere we call them the same GR I think is splitting hairs. People who work in libraries would say there is one work and multiple manifestations. 14:10:39 -TimBL 14:12:12 (TimBL departs) 14:13:36 jar: Suppoose yoou have names for documents, and a way to get the document given the name. Then nobody would use http protocol. So if I mention a particular paper, I'm referring to *that* paper, independent of anything the web does. 14:14:35 ... Eg could put an MD5 in the URI, and then you could check to see if it really is the one I meant. 14:15:25 In this fantasy world, the URI names the document, independent of what the web or Internet does. 14:15:42 You could feed the URI to some magic resolving mechanism to get the paper. 14:18:26 So if these 'names' worked beautifully, why would anyone use an http URI? 14:19:44 In HTTP, the protocol is authoritative for the URI. 14:21:40 Names would have idealized persistence. 14:23:16 Resolution protocol: Fetch an octet stream through undetermined means, if md5 is right then ok, otherwise try another 14:28:47 People would like to have names for use in their href= 14:29:12 dbooth: RDF statements are tied to particular times 14:32:21 Given HTTP, no way to tell the difference between a mistake an an intentional change 14:33:42 roles: uri owner, statement author, consumer 14:39:33 in general the consumer won't be able to distinguish "correct" resolution from "incorrect" resolution. 14:50:37 -DBooth 14:50:39 -jar 14:50:39 TAG_(AWWSW)9:00AM has ended 14:50:40 Attendees were DBooth, TimBL, jar, Alan_Ruttenberg 14:50:55 rrsagent, make logs public 14:51:03 rrsagent, draft minutes 14:51:03 I have made the request to generate http://www.w3.org/2009/03/31-awwsw-minutes.html jar 14:51:11 rrsagent, pointer 14:51:11 See http://www.w3.org/2009/03/31-awwsw-irc#T14-51-11 15:21:31 Zakim has left #awwsw