- From: Antoine Zimmermann <antoine.zimmermann@emse.fr>
- Date: Tue, 11 Sep 2012 21:54:33 +0200
- To: Richard Cyganiak <richard@cyganiak.de>
- CC: RDF Working Group WG <public-rdf-wg@w3.org>
Le 11/09/2012 19:10, Richard Cyganiak a écrit : > On 11 Sep 2012, at 12:29, Antoine Zimmermann wrote: >> In "Basics": a dataset A is consistent with a dataset B if both can >> be true at the same time. What you write looks more like >> "modularity" in a logical sense. > > Fixed. > >> T1.1: classically, entailment would be defined between datasets. >> RDF entailment is between RDF graphs, FOL entailment is between FOL >> formulas, DL entailment is between DL ontologies, etc. I think it's >> better to say that RDF graphs are assimilated to RDF datasets that >> only have a default graph. Thus, with harmless abuse of notations, >> we can say: >> >> { G } dataset-entails G >> >> and >> >> G dataset-entails { G } >> >> Then you don't have to distinguish T1.X and T2.X. > > To me, it seems simpler to consider dataset-interpretations as being > able to interpret both RDF datasets and RDF graphs. Then we can talk > of a dataset-interpretation as satisfying both RDF datasets and RDF > graphs. And from that we get all the notions of entailment, > contradiction, and so on, between graphs and datasets. This way, it > requires *no* abuse of notation, not even harmless abuse ;-) > > I think it's a fairly small matter and maybe should be best left to > the editors. Agreed. >> T2.X: we should not repeat tests that are already present in RDF >> test cases, OWL test cases, etc. > > Note, I wrote the test cases just to illustrate the effects of the > semantics, in order to facilitate discussion and give other WG > members some confidence that the stuff we're proposing here isn't > entirely absurd. At this point, I don't think it matters whether the > test cases are redundant or complete, as long as they help us > understand, and uncover potential issues. Ok, so it's all right. >> We can define meta-tests that can be used with the existing test >> cases to generate concrete tests automatically: > > You're talking about a formal test suite, a la RDF Test Cases? Yes, > for that purpose it would make sense to automatically generate such > meta-tests. > > What I wanted to do for now is just provide examples that show the > semantics in action. For this purpose, I think “non-meta” test cases > with actual triples work better. > > It's probably worth revisiting these meta-tests once we talk about a > formal suite of test cases. Ok. > <snip> >> >> T5.2: this test is wrong. The empty graph does not entail >> >> :n {} >> >> in general. > > You're right, good catch. Fixed by saying only that :g1 {} entails > the empty dataset. > >> To entail this, n must be in the vocabulary of the interpretation. >> This means that the empty graph RDF-dataset-entails: >> >> rdf:type {} >> >> for instance, but not: >> >> owl:sameAs {} > > Yeah, that's a bit weird. I guess one way of changing this would be > to make IGEXT a *partial* function from the resources in I_d to the > set of RDF graphs? Perhaps, have to check the implications. Also, one way to change this is to do what Pat suggested, as you say below. > >> That's one possible argument in favour of getting rid of the >> dependency to a vocabulary. > > I think Pat mentioned that he'd prefer to do that, for all of RDF > Semantics. > > Perhaps best treated as an issue orthogonal to the semantics of > datasets. Sure. >> T6.X simply say we have open world assumption. Any entailment valid >> on a subset of an RDF dataset are valid for said dataset. > > Yup, but I think it's worth pointing out, for clarity. Again, this is > not a proposal for a complete and formal test suite :-) I understand. It's fine. > > <snip> >> >> There are a few more tests that are worth putting in: >> >> An inconsistent graph in a named graph allows one to derive any >> conclusion within the graph, but does not affect other named >> graphs, nor the default graph. >> >> """ If a test case exists for entailment regime E such that G is >> E-inconsistent, then: >> >> :n { G } E-dataset-entails :n { :s :p :o } >> >> but does not entail: >> >> { :s :p :o } >> >> nor >> >> :m { :s :p :o } """ > > Good one. Added (in non-meta style) as T12.1-3. > >> IRIs in different named graphs can denote different things: >> >> """ { :s owl:sameAS "a" } :n { :s owl:sameAs "b" } :m { :s >> owl:sameAs "c" } >> >> is OWL-dataset-consistent. """ > > Good one too! Added as T13.1. > >> Graph IRIs do not necessarily denote a graph: >> >> """ { :n owl:sameAs "a" } :n { :s :p :o } >> >> is OWL-dataset-consistent. """ > > Ah, nice way of showing this. Added as T11.3. > >> Other tricky test case: >> >> { :p rdfs:range xsd:boolean . :s :p :n, :m, :o . } :n { :q >> rdfs:range xsd:string . :x :q :y } :m { :q rdfs:range rdf:HTML >> . :x :q :y } :o { :q rdfs:range rdf:langString . :x :q :y} >> >> is RDFS-dataset-inconsistent. """ > > Very clever! But I believe this is actually RDFS-dataset-consistent; > it only becomes inconsistent under D-dataset-entailment? Absolutely right, my mistake. Basically, I wanted to avoid relying on OWL to show that the RDF semantics suite are providing difficult cases too. > I've added it as T14.1. > >> Note that this would be consistent if IGEXT was a function from >> IRIs to graphs instead of resources to graph. > > It would also be consistent if you wouldn't be using booleans as > graph names :-) Of course. But test cases have to contain corner cases. Those are the ones that make implementations robust. AZ > > Best, Richard > > > >> >> >> >> HIH --AZ. >> >> >> Le 10/09/2012 18:30, Richard Cyganiak a écrit : >>> All, >>> >>> http://www.w3.org/2011/rdf-wg/wiki/TF-Graphs/Minimal-dataset-semantics#Test_cases >>> >>> >>> I've added a number of test cases and examples to the Minimal >>> Dataset Semantics wiki page. There are also test cases that try >>> to specifically show what's at stake in the various open issues. >>> No one has reviewed this yet, so expect some errors. >>> >>> I think this should be a good basis for further discussion. I >>> think it would be helpful for Wednesday's call if everyone had >>> read through these test cases. Please feel free to ask questions >>> and propose additional examples and test cases! >>> >>> Two other things that I'd quite like to see before we can call >>> the proposal complete: >>> >>> 1. Some thinking on how it addresses our graph use cases. (Do we >>> have an “official” list of those? I've lost track with all the >>> various documents.) >>> >>> 2. Some examples for semantic extensions, in order to show that >>> various other proposed semantics can actually be done as proper >>> semantic extensions of this minimal dataset semantics. >>> >>> Best, Richard >>> >> >> >> -- Antoine Zimmermann ISCOD / LSTI - Institut Henri Fayol École >> Nationale Supérieure des Mines de Saint-Étienne 158 cours Fauriel >> 42023 Saint-Étienne Cedex 2 France Tél:+33(0)4 77 42 83 36 >> Fax:+33(0)4 77 42 66 66 http://zimmer.aprilfoolsreview.com/ >> > > -- Antoine Zimmermann ISCOD / LSTI - Institut Henri Fayol École Nationale Supérieure des Mines de Saint-Étienne 158 cours Fauriel 42023 Saint-Étienne Cedex 2 France Tél:+33(0)4 77 42 83 36 Fax:+33(0)4 77 42 66 66 http://zimmer.aprilfoolsreview.com/
Received on Tuesday, 11 September 2012 19:55:35 UTC