- From: Simon Spero <sesuncedu@gmail.com>
- Date: Sat, 21 May 2016 15:16:24 +0000
- To: Nathan Rixham <nathan@webr3.org>
- Cc: Harry Halpin <hhalpin@ibiblio.org>, Melvin Carvalho <melvincarvalho@gmail.com>, Pat Hayes <phayes@ihmc.us>, Phil Archer <phila@w3.org>, Semantic Web IG <semantic-web@w3.org>
- Message-ID: <CADE8KM4=TdKsmitczK69vCTRK7ZGEYo+A7g4P9w==9RR0pQxmw@mail.gmail.com>
sameAs is correct, though under under the OWL Direct Semantics, it may not give all the desirable entailments if the IRI denotes a Class or *Property. Using equivalentClass / equivalentProperty axioms gives desired result. On the other hand, there is no specific reason not to continue using http: IRIs as names, and using a different protocol if those names are converted to locators. Simon On Sat, May 21, 2016, 10:40 AM Nathan Rixham <nathan@webr3.org> wrote: > Why not owl:sameas? Is it technically incorrect? > > If it's the correct property to use and widely understood + supported, > saying it's been used incorrectly previously doesn't hold much weight as an > argument against using it correctly to solve a web scale real world problem > simply. > On 21 May 2016 2:28 pm, "Simon Spero" <sesuncedu@gmail.com> wrote: > >> There is no necessary between an IRI used in any position in an RDF >> triple, and any #$InformationBearingObject that may be returned as a result >> of interpreting the lexical form of such an IRI as a set of procedural >> directives. >> >> There is thus no reason why Stigmergic Web applications cannot interpret >> these lexical forms such that they perform different actions, with no >> required changes anywhere else. >> >> Meet the new sameAs, same as the old sameAs. >> >> Simon >> On May 21, 2016 12:53 AM, "Harry Halpin" <hhalpin@ibiblio.org> wrote: >> >>> Given that the Semantic Web use of HTTP URIs basically means that any >>> use of 'follow your nose' is easily subverted by anyone with access to the >>> raw HTTP stream, we should just update the Semantic Web specs and reasoners >>> so that TLS is enforced by default and HTTP = HTTP(S). >>> >>> While it is true that some normal web-pages *can* serve different >>> content at TLS than non-TLS, it's currently considered pathological. >>> >>> If the Semantic Web doesn't gracefully deal with the upgrade from HTTP >>> to TLS, it will date itself quite quickly and will not be usable for any >>> real-world usage (notice almost all major sites now are moving to TLS) >>> outside of enterprise use within a firewall or usages where there's no >>> 'follow your nose' effort. In the latter case, I'm not sure if using HTTP >>> URIs makes sense to begin with. >>> >>> Note that the upgrade should be relatively cost-free, see the "Let's >>> Encrypt" effort for free TLS certs. >>> >>> On Fri, May 20, 2016 at 6:04 PM, Pat Hayes <phayes@ihmc.us> wrote: >>> >>>> >>>> On May 20, 2016, at 5:02 PM, Nathan Rixham <nathan@webr3.org> wrote: >>>> >>>> .... >>>> An x:alias predicate which asserts that one name (IRI) is an alias of >>>> another name (IRI) would be very useful. <a#b> x:alias <c#d> . >>>> >>>> An x:canonical predicate which asserts <a#b> x:alias <c#d> . and that >>>> <a#b> is the preferred IRI more useful still. >>>> >>>> >>>> Just an observation - it may be that practical needs override formality >>>> - but this is not legal according to the RDF semantics. The truth of a >>>> triple aaa R bbb depends only on what the IRIs in the triple, in particular >>>> aaa and bbb, *denote*, not on their syntactic form. So x:alias would have >>>> the same semantics as owl:sameAs (and we all know what happened to *that* >>>> when it got out into the wide world.) >>>> >>>> We could sneak around this by declaring (contrary to the normative >>>> semantics, but still...) that x:alias is a new kind of property, one that >>>> quotes its arguments and is therefore referentially opaque. There would >>>> have been a time when I would have opposed this idea with some vigor, but >>>> age has mellowed me. And the internal semantic coherence of the Web can >>>> hardly get worse than it is already, so what the hell. Just be ready for >>>> the truly awful muddle that will arise when x:alias bumps into owl:sameAs >>>> and reasoners try to figure out what the consequences might be. >>>> >>>> A better solution would be to invent, and have everyone adopt[**], a >>>> IRI-quoting-IRI convention, something like x:theIRI# , with the semantics >>>> that x:theIRI#someOtherIRI always denotes someOtherIRI. (Maybe this would >>>> need some clever character-escaping? I leave that to others to work out.) >>>> Then x:theIRI#a#b x:alias x:theIRI#c#d would mean what you want to express, >>>> above. >>>> >>>> Pat Hayes >>>> >>>> [**] There's the rub, of course. >>>> >>>> >>>> Using syntax shortcuts you could add the following triple to the turtle >>>> document at https://www.w3.org/1999/02/22-rdf-syntax-ns# >>>> >>>> rdf: x:canonical <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . >>>> >>>> Result: >>>> <http://www.w3.org/1999/02/22-rdf-syntax-ns#> a owl:Ontology . >>>> <https://www.w3.org/1999/02/22-rdf-syntax-ns#> a owl:Ontology . >>>> >>>> >>>> Point 2: >>>> >>>> Using a 307 redirect for the semantic is nice, but practically click >>>> http://www.w3.org/ns/dcat# and you are redirected, refresh and you >>>> find the client does use the redirected url for subsequent requests. >>>> >>>> As a general person or developer search w3.org for dcat and the >>>> results are https://www.google.com/search?q=site:w3.org%20dcat - the >>>> url listed is the https url. >>>> >>>> Usage of the https IRIs will enter the web of data ever increasingly, >>>> whether people say the http one should be used or not. >>>> >>>> Point 3: >>>> >>>> Practically taking a simple real world step like migrating to a CDN >>>> will often give http/2+tls thus https IRIs automatically. >>>> >>>> Test case: >>>> >>>> Alice has a wordpress/drupal site that publishes RDF automatically. She >>>> doesn't know about the RDF. >>>> Alice clicks the "free CDN" button in her hosting account. >>>> Alice now has https and http IRIs in RDF on both http:// and https:// >>>> protocols. >>>> >>>> Personally I cannot think of anything easier than as best practise >>>> adding a single triple to rdf documents when migrating protocols. Anything >>>> within the black box will fail and be implemented incorrectly. >>>> >>>> On Sat, May 21, 2016 at 12:42 AM, Melvin Carvalho < >>>> melvincarvalho@gmail.com> wrote: >>>> >>>>> >>>>> >>>>> On 20 May 2016 at 20:08, Phil Archer <phila@w3.org> wrote: >>>>> >>>>>> Not a moan about spam, or a CfP, but an actual discussion point, yay! >>>>>> >>>>>> I've just blogged about our use of HTTPS across www.w3.org which >>>>>> raises some questions for this community. Please see >>>>>> https://www.w3.org/blog/2016/05/https-and-the-semantic-weblinked-data/ >>>>> >>>>> >>>>> On the one hand more security is a nice to have, but on the other, >>>>> Cool URIs dont change. It's really hard to estimate the cost, and >>>>> unintended consequences of changing URIs. But my feeling is that we >>>>> systematically underestimate it. >>>>> >>>>> IMHO, It's kind of a shame that http wasnt made secure, and that a new >>>>> scheme https was invented. >>>>> >>>>> >>>>>> >>>>>> >>>>>> Comments welcome. >>>>>> >>>>>> Thanks >>>>>> >>>>>> -- >>>>>> >>>>>> >>>>>> Phil Archer >>>>>> W3C Data Activity Lead >>>>>> http://www.w3.org/2013/data/ >>>>>> >>>>>> http://philarcher.org >>>>>> +44 (0)7887 767755 >>>>>> @philarcher1 >>>>>> >>>>>> >>>>> >>>> >>>> ------------------------------------------------------------ >>>> IHMC (850)434 8903 home >>>> 40 South Alcaniz St. (850)202 4416 office >>>> Pensacola (850)202 4440 fax >>>> FL 32502 (850)291 0667 mobile >>>> (preferred) >>>> phayes@ihmc.us http://www.ihmc.us/users/phayes >>>> >>>> >>>> >>>> >>>> >>>> >>>
Received on Saturday, 21 May 2016 15:17:04 UTC