**** BEGIN LOGGING AT Thu Oct 5 09:02:47 2006 Oct 05 09:02:47 --> You are now talking on #tagmem Oct 05 09:02:47 --- Topic for #tagmem is see you in Vancouver http://www.w3.org/2001/tag/2006/10/04-agenda.html Oct 05 09:02:47 --- Topic for #tagmem set by DanC at Wed Sep 27 12:55:06 2006 Oct 05 09:03:07 --> timbl (timbl@208.181.171.17) has joined #tagmem Oct 05 09:03:24 --> Vincent (quint@208.181.171.17) has joined #tagmem Oct 05 09:06:58 Meeting: TAG F2F (Morning) Oct 05 09:06:58 Date: 5 Oct 2006 Oct 05 09:06:58 Agenda: http://www.w3.org/2001/tag/2006/10/04-agenda.html Oct 05 09:06:58 Chair: Vincent Oct 05 09:06:58 Scribe: Norm Oct 05 09:06:58 ScribeNick: Norm Oct 05 09:07:08 Present: Tim Berners-Lee, Dan Connolly, Noah Mendelsohn, David Orchard, Vincent Quint, T.V. Raman, Henry Thompson, Norm Walsh Oct 05 09:07:08 Regrets: Ed Rice Oct 05 09:07:02 --> RRSAgent (rrs-loggee@128.30.52.30) has joined #tagmem Oct 05 09:07:02 logging to http://www.w3.org/2001/tag/2006/10/05-morning-minutes.log Oct 05 09:07:04 --- You're inviting Zakim to #tagmem (irc.w3.org) Oct 05 09:07:04 --> Zakim (rrs-bridgg@128.30.52.30) has joined #tagmem Oct 05 09:08:48 * DanC_lap is running a few minutes behind... will be there in 5min Oct 05 09:09:39 * Norm points to http://www.flickr.com/photos/ndw/sets/72157594314092638/ for your amusement Oct 05 09:13:50 http://www.w3.org/2001/tag/2006/acme/Overview.html for norm Oct 05 09:13:50 --> Noah (noah_mende@208.181.171.17) has joined #tagmem Oct 05 09:13:56 --> tvraman (raman@208.181.171.17) has joined #tagmem Oct 05 09:14:08 --> ht_vancouver (ht@128.30.52.30) has joined #tagmem Oct 05 09:14:23 * Norm points to http://www.flickr.com/photos/ndw/sets/72157594314092638/ for your amusement Oct 05 09:16:53 <-- DanC_lap has quit (Client exited) Oct 05 09:17:06 --> DanC_lap (connolly@128.30.52.30) has joined #tagmem Oct 05 09:17:43 http://www.platinax.co.uk/news/30-09-2006/google-addresses-w3c-link-selling/ Oct 05 09:22:13 code away ...http://www.google.com/codesearch Oct 05 09:23:00 --> dorchard (0c8208db@128.30.52.23) has joined #tagmem Oct 05 09:24:51 Topic: Issue XMLVersioning-41 Oct 05 09:25:01 http://www.ltg.ed.ac.uk/~ht/language.html Oct 05 09:27:35 * dorchard norm, you had a pics URI/ Oct 05 09:27:48 * Norm points to http://www.flickr.com/photos/ndw/sets/72157594314092638/ for your amusement Oct 05 09:28:26 HT: introduces "XML Languages, entailment and versioning": http://www.ltg.ed.ac.uk/~ht/language.html Oct 05 09:29:16 s/HT: /HT / Oct 05 09:30:57 HT: In the model-theoretic view, truth is what matters but "truth" isn't at the core of many of our languages. Oct 05 09:32:39 HT: How are we going to talk about the text in different languages with respect to the information they contain. This is an attempt to answer that question. Oct 05 09:32:46 When Henry's done, I'd like to take a few minutes to talk about some of the ideas I've had in this space. I think they're complementary to where Henry is going, though approached a bit less formally. Oct 05 09:32:48 s/contain./contain?/ Oct 05 09:34:19 HT: In the traditional model-theoretic view, the distinction between concrete and abstract syntaxes isn't very important. But in our story, it is. Oct 05 09:37:35 Three levels: Oct 05 09:37:49 1. The concrete syntax, defined by BNF or DTD/Schema or ... Oct 05 09:38:05 2. The data model, Java classes, schema components, ... Oct 05 09:38:15 3. The model out in the real world Oct 05 09:38:33 HT: For XML languages, it's more complex. Oct 05 09:39:35 HT: Theta maps from a syntax to a data model Oct 05 09:39:57 HT: Phi maps from the data model to the real world model Oct 05 09:41:17 HT: Consider SVG: there's a Theta that maps from XML to the infoset, then there's a Theta that maps from infoset to the SVG data model, then there's a Phi that maps from that data model to the bitmaps/splines/... Oct 05 09:41:39 Noah: Can't we look at this as having several languages in play? Oct 05 09:42:45 HT: I don't think we can ignore any of the three levels, but can we focus on 1 and 2? Oct 05 09:42:58 HT: Goal is not to talk about what kinds of models or Phi relations there are. Oct 05 09:43:13 HT: There are an enormous number of them. I think we can avoid going there an still say useful things. Oct 05 09:43:25 Dan: I'm certain that we can't ignore level 3. Oct 05 09:44:33 HT: We can't get by with the traditional truth definition of entailment. Oct 05 09:44:51 HT: Consider schema, SVG, and purchase order XML. These have different flavors. Oct 05 09:45:01 To clarify, I was saying that one way to tell the story about the different abstractions that can be inferred from an SVG text. Language 1 is XML+Infoset. It tells you that given an SVG text you can infer things like which element has which parent. Another "language" extracts from the same texts information about, e.g., which circles should be drawn on a screen or page. Oct 05 09:45:06 HT: Consider the distinction between "snow is white" and "I hearby pronounce you man and wife" Oct 05 09:45:30 HT: You can't say anything about the truth or falsehood of the second, it changes the state of the world. Oct 05 09:46:00 HT: Two kinds of fit, word-to-world (snow is white) and world-to-word (I hereby pronounce you...) Oct 05 09:46:04 s/hearby/hereby/ Oct 05 09:46:42 HT: World-to-word or "performative" sentences change the world to match the words. Oct 05 09:47:29 TBL: we've modelled these perfomatives in RDF by using the empty URI reference: { <> a Invoice } Oct 05 09:47:39 HT: In between declarative and performative we also have imperatives. Oct 05 09:48:39 HT: XML Schema is declarative: given a schema component and an infoset, the schema is true (satisfied) or false (not satisified) of/by the infoset Oct 05 09:49:28 Noah: I expected to hear a story about schema documents. That you'd say the information that you got out of the schema document is a set of element/attribute declarations. Oct 05 09:49:42 HT: That's where I'm going but from a different direction. Oct 05 09:50:38 DanC: The schema document isn't true or false without an infoset. Oct 05 09:50:52 HT: This is just like "it's raining". That's not true independent of when and where. Oct 05 09:51:09 Noah: There are lots of other things that you can ask or say about a schema. Oct 05 09:51:49 HT: SVG can go either way. Given an SVG dataset and a bitmap, the dataset is true or false of/by the bitmap. Or you can view it as a set of instructions to construct a bitmap (to change the world) Oct 05 09:52:30 TBL: An SVG document isn't a statement or sentence, it's a noun phrase. Oct 05 09:52:30 <-- Vincent has quit (Ping timeout) Oct 05 09:53:03 HT: Until you've said what you're going to do with it, there's a limit to what you can say about versioning it. Oct 05 09:53:31 HT: The purchase order is definitely performative. Receipt of a PO means package and ship the goods. Oct 05 09:53:37 TBL: "I hereby order something" Oct 05 09:54:46 HT: Footnote: you can still frame all of this in terms of claims on the world. Declaratives are true iff they match the world. Performatives can be viewed as pre and post conditions. Oct 05 09:54:56 HT: Consider the traffic light (the RGB language) Oct 05 09:55:44 HT describes the language and the UML diagram (data model) Oct 05 09:57:07 HT: The RGB language has a declarative interpretation. An instance of RGB is satisfied by a bitmap iff all its lights are satisfied by that bitmap. Oct 05 09:57:17 s/bitmap./bitmap.../ Oct 05 09:58:53 HT: The RGB language has a performative interpretation. Henry describes the performative semantics. Oct 05 10:01:15 HT: Finally entailment. We can define entailment for either approach to the semantics of RGB Oct 05 10:02:58 HT: Entailment for the declarative semantics: An instance of RGB (A) entails another instance of RGB (B) iff all the bitmaps that satisfy A also satisfy B. Oct 05 10:03:51 HT: Entailment for the performative semantics: We say that a message A entails a message B iff for all possible initial states, the response to A performs at least all the actions involved in the response to B. Oct 05 10:07:53 HT: Can we appeal to entailment w/o appealing to the model except insofar as entailment presupposes it? Oct 05 10:08:35 --> Vincent (quint@208.181.171.21) has joined #tagmem Oct 05 10:09:01 TBL: I don't think you can do entailment for SVG. Oct 05 10:09:08 TBL: Consider an SVG that draws a purchase order. Oct 05 10:09:58 TBL: SVG entailment would allow a purchase order of 17 items to be substituted for a purchase order for 3 items. Oct 05 10:10:18 TBL: The entailment at the purchase order will be completely different. Oct 05 10:10:34 DanC: The entailment relationship will preserve which pixels are red and green. Oct 05 10:11:00 Noah: It gets worse. When you version a language, if you're looking for only new documents will do new things, then I think that makes sense. Oct 05 10:11:18 Noah: The same PO in the SVG 1 spec will render the same way in the SVG 2 spec. Oct 05 10:11:35 Noah: That's not true of all languages. Oct 05 10:12:02 Noah: It's circular to say that "that is compatible" in the framework. Oct 05 10:12:50 DanC: I think it would be useful to say that as long as your language satisfies these criteria then you don't have to say anymore. But if it defines compatibility some other way, you have to think really hard. Oct 05 10:13:14 HT: Is the functional assumption ok for Theta? Oct 05 10:14:11 HT: The notion of the data model (in this paper) is too simple--any language with keys in it may be mapped directly into updates at the model level, voilating the implicit appeal to some kind of context-free abstract syntax kind of story. Oct 05 10:15:07 HT: An
might be interpreted immediately as an update to a database row keyed by name. Oct 05 10:15:23 TBL: When an update has been made, there's some information content in that. Oct 05 10:15:57 TBL: When you're accumulating information, then special things occur. There's a 1:1 correspondence with the entailment in each of those cases. Oct 05 10:16:56 HT: There are also conditional statements to be considered. There's was a simplifying assumption that needs to be unpacked. I'm not saying there are going to be catastrophes, but... Oct 05 10:17:12 HT: Consider adding . Oct 05 10:17:44 HT: This results in less information in the data model. Oct 05 10:18:44 Noah: Doesn't this depend on your point of view? If your model is a running list of which attributes will be validated, then its not monotonic. Oct 05 10:18:51 HT: This is about two different schema documents, so there's no time component Oct 05 10:18:51 <-- dorchard has quit (Quit: CGI:IRC (EOF)) Oct 05 10:19:14 Noah: If you modeled it in a way that followed the syntax more closely you might get different results. Oct 05 10:20:18 Critical point seems to have been that this is an existence proof of a certain class of problems. Oct 05 10:20:51 Noah: We're trying to teach users what information is in their documents. Oct 05 10:21:05 HT: It's perfectly coherent to define a Theta that isn't additive. Oct 05 10:21:43 Noah: It's coherent, but is it the case that whenever you define Theta that way, could have defined it another way? Oct 05 10:22:24 HT: The punch line is that if this works, we'll have an opportunity to state to levels of relationship which will ground the versioning paper: Oct 05 10:22:36 1. Two texts from a language are equivalent if they correspond to the same data model. Oct 05 10:22:43 2. A text A from a language is compatible with another text B if A corresponds to a data model which entails the data model corresponding to B. Oct 05 10:23:02 HT: Attributes with single and double quotes, for example, are data model equivalent. Oct 05 10:25:10 HT: In general, this is informal. In a language with additive semantics, then any two texts where one text is a superset of another, the bigger one will entail the smaller one. Oct 05 10:25:23 DanC: That's the definition of monotonicity. Oct 05 10:25:51 TBL: This "compatible with" is something we needed when we were talking about I1 and I2. Oct 05 10:27:20 Noah: I have a text A and in terms of Language 1, certain things follow. Oct 05 10:27:42 Noah: Now I kept the text, but I sent it to someone else using Language 2. Oct 05 10:27:47 q+ Oct 05 10:27:47 * Zakim sees timbl on the speaker queue Oct 05 10:28:12 Noah: I thought that we were going to have statements that told us something about that case. Oct 05 10:31:03 HT: 3. A language L1 is compatible with a language L2 with respect to a text A if the data model corresponding to A in L1 entails the data model corresponding to A in L2. Oct 05 10:31:31 TBL: You talk about entailment in terms of two sets of actions. This is at level 3. Oct 05 10:32:07 TBL: Two languages with two different data models can have the same information (SVG and HTML documents that both say to close the door) Oct 05 10:32:39 TBL: If you allow yourself to say that the semantics of one entail the semantics of the other, then we can tie these things together. Oct 05 10:32:53 TBL draws a picture Oct 05 10:35:06 TBL: It would be nice if we could talk about sets of instructions or claims (some philosophical background work necessary) Oct 05 10:35:12 (I actually did come up with the correspondence timbl just asked "you and the philosophers" to come up with... pointer coming...) Oct 05 10:36:47 TBL: If we have a PO in XML and another in RDF, we need to be able to tell if they are compatible in the real world. Oct 05 10:37:11 --> dorchard (d0b5ab11@128.30.52.23) has joined #tagmem Oct 05 10:37:38 (how to make PHI functional: http://lists.w3.org/Archives/Public/www-tag/2006Sep/0040.html ) Oct 05 10:37:41 HT: I'm not comfortable talking about the real world as information. Oct 05 10:37:56 q+ Oct 05 10:37:56 * Zakim sees timbl, DanC_lap on the speaker queue Oct 05 10:38:13 TBL: For me level three isn't the lawnmower, it's information about the lawnmower. Oct 05 10:38:26 ack timbl Oct 05 10:38:26 * Zakim sees DanC_lap on the speaker queue Oct 05 10:40:18 DanC: Returning to the analogy between the "functional" terminology that Oct 05 10:40:18 you objected to, Pat, and the conventional terminology, here's Oct 05 10:40:18 what I have in mind... Oct 05 10:40:18 In the conventional terminology, "An argument is valid if the truth of Oct 05 10:40:18 its premises guarantees the truth of its conclusion" (odd; that's Oct 05 10:40:18 easy to find in Suber's stuff, but I can't find it in wikipedia). Oct 05 10:40:18 That glosses over a bunch of stuff that you have to elaborate Oct 05 10:40:18 in order to talk about multiple (versions of) languages. Oct 05 10:40:18 To elaborate, an argument P to Q is L-valid iff for Oct 05 10:40:18 all L-interpretations I, if I(P) is true, then I(Q) is true. Oct 05 10:40:18 (the Wikipedia article calls them L-structures rather Oct 05 10:40:18 than L-interpretations, I think.) Oct 05 10:40:18 To map to the "functional meaning" terminology, flip things Oct 05 10:40:18 around just a little bit and let the "L-meaning" of P be a function Oct 05 10:40:18 from interpretations to True/False. Then we'd say: Oct 05 10:40:18 an argument from P to Q is valid iff for all interpetations I, Oct 05 10:40:18 if L-meaning(P)(I) is true, then L-meaning(Q)(I) is true. Oct 05 10:40:18 Does that make sense, Pat? And do you see how it allows Oct 05 10:40:18 us to speak of _the_ meaning that SVG version 1.23 gives Oct 05 10:40:18 to the text "..."? Oct 05 10:40:29 ack danc Oct 05 10:40:29 * Zakim sees no one on the speaker queue Oct 05 10:41:32 HT: The label Phi is not a label for the relationship between the data model and the set of claims it makes. It's a name for "is domain of discourse of". It maps to the real world. Oct 05 10:42:08 HT: It's a separate question if there's a function that maps from that data model to the set of claims. Oct 05 10:42:14 q+ to prose we break, and when we return, we edit a UML diagram, with me projecting, for say, 30 to 45 minutes Oct 05 10:42:14 * Zakim sees DanC_lap on the speaker queue Oct 05 10:42:35 ack danc Oct 05 10:42:37 DanC_lap, you wanted to prose we break, and when we return, we edit a UML diagram, with me projecting, for say, 30 to 45 minutes Oct 05 10:42:38 * Zakim sees no one on the speaker queue Oct 05 10:43:26 Chair calls a break Oct 05 10:50:08 TBL's diagram http://www.w3.org/2001/tag/2006/10/04-whiteboard-2.jpg Oct 05 11:05:26 <-- timbl has quit (Connection reset by peer) Oct 05 11:05:50 <-- Noah has quit (Connection reset by peer) Oct 05 11:07:28 --> timbl (timbl@208.181.171.17) has joined #tagmem Oct 05 11:09:13 <-- ht_vancouver has quit (Ping timeout) Oct 05 11:10:06 --> ht_vancouver (ht@128.30.52.30) has joined #tagmem Oct 05 11:12:50 Noah: What's the story we tell about information in Dave's finding? I was struggling with a few things. Oct 05 11:13:24 Noah: It seemed like a data model and that isn't the same for RDF/XML/key-value pairs, etc. Oct 05 11:13:36 Noah: The idea that came to me is that having information is being able to answer questions. Oct 05 11:13:49 ...I start out not knowing anything. Handed a document, I still don't know anything. Oct 05 11:14:10 ...Handed a description of the language that the document is written in, I can now start to answer questions. I have information. Oct 05 11:14:21 ...By phrasing it this way, I can cover not only the information but also it's structure. Oct 05 11:15:05 ...The infoset language lets me answer questions like "what's the root element of the document", etc. Oct 05 11:15:13 ...Now I have access to structure. Oct 05 11:16:03 ...But some folks want to be able to connect information to things in the real world. Oct 05 11:16:25 ...Not all languages aspire to that. Consider keyword/value pairs. Oct 05 11:17:54 like plists, i imagine Oct 05 11:18:22 ...Like all languages, the spec lets you answer certain questions. You can say what the value is for a given keyword. But that's pretty much it. Oct 05 11:18:37 ...But what if I do want to do RDF? Then the questions I get to answer in that language are much deeper and more interesting. Oct 05 11:19:15 ...We're also looking for a subset/superset relationship. I think it's in some sense pretty clear. To the extent that in two different languages the same text allows you to answer an overlapping set of questions, you've got a story to tell. Oct 05 11:20:02 DanC: You can write a language where the part 3 bit is elements. Oct 05 11:20:21 ...That's the more traditional way. There's syntax and semantics. Oct 05 11:20:54 ...This comes back to the discussion of SVG semantics. If you have an SVG purchase order, you have two languages. The SVG language tells you what pixels to turn on, the other language let's you order things. Oct 05 11:21:50 Noah: This seems like the kind of story you could tell in simple words. Oct 05 11:22:22 ...In my formulation, there' just questions. It might be that this is the same as what Henry did, but I can't prove that. Oct 05 11:22:47 DanC: I'm pretty sure that we're going to need more than that to do the finding. Oct 05 11:22:47 <-- dorchard has quit (Quit: CGI:IRC (EOF)) Oct 05 11:23:00 Noah: Clearly where I say "question" you want something more formal. Oct 05 11:23:27 DanC: I'm not convinced that three levels is necessary Oct 05 11:23:37 HT: I'm pretty sure that they are. Oct 05 11:24:20 --> Noah (noah_mende@208.181.171.17) has joined #tagmem Oct 05 11:28:39 DanC engages in thirty minutes of joint editing on the UML versioning diagram Oct 05 11:35:39 * Norm still doesn't grok UML Oct 05 11:42:34 <-- timbl has quit (Connection reset by peer) Oct 05 11:42:49 <-- Noah has quit (Connection reset by peer) Oct 05 11:44:30 --> timbl (timbl@208.181.171.17) has joined #tagmem Oct 05 11:45:16 <-- ht_vancouver has quit (Ping timeout) Oct 05 11:54:33 --> Noah (noah_mende@208.181.171.17) has joined #tagmem Oct 05 11:55:26 Hmm. Was disconnected. In case it wasn't minuted, it seems important to me that the commonsense definition of "Information Set" is "All the things you can convey using this language". Oct 05 11:55:42 * Norm thanks Noah Oct 05 11:59:20 link, again http://lists.w3.org/Archives/Public/www-tag/2006Sep/0040.html Oct 05 12:02:22 --> ht_vancouver (ht@128.30.52.30) has joined #tagmem Oct 05 12:02:29 http://www.ltg.ed.ac.uk/~ht/language.html Oct 05 12:16:11 * Noah Noah things that Dave may have reserved our lunch table for right now? Oct 05 12:18:19 Recessed for lunch Oct 05 12:20:46 <-- timbl has quit (Quit: timbl) Oct 05 12:20:48 <-- Noah has quit (Ping timeout) Oct 05 12:46:17 * Zakim excuses himself; his presence no longer seems to be needed Oct 05 12:46:17 <-- Zakim (rrs-bridgg@128.30.52.30) has left #tagmem Oct 05 14:05:18 --> timbl (timbl@208.181.171.17) has joined #tagmem Oct 05 14:06:47 --> dorchard (d0b5ab11@128.30.52.23) has joined #tagmem Oct 05 14:06:57 * dorchard my suggestion for dinner is tojo http://www.tojos.com/