- From: Simon Miles <simon.miles@kcl.ac.uk>
- Date: Thu, 14 Jul 2011 11:26:05 +0100
- To: Provenance Working Group WG <public-prov-wg@w3.org>
Hi Paul, > Thing = Bob or Entity State Sorry to be difficult, but... BOB is currently defined in terms of Entity State, so if they are both replacing Thing it's a circular definition. Alternatively, they are two separate terms, one of which replaces Thing, making three along with Entity. > Finally I would suggest that the participates divide issues into two threads if possible (e.g. Model vs ivp) I agree with the sentiment, but I think maybe the key issues (specifying models in a helpful way, definition of entity, definition of IVP) are all tangled up at the moment. If I can see a possible way to split off a topic, I will try to do so. Thanks, Simon > > Thanks > Paul > > On Jul 14, 2011, at 8:40 AM, Graham Klyne <GK@ninebynine.org> wrote: > >> Myers, Jim wrote: >>> I'm having a hard time understanding how this discussion changes the model (or what version/interpretation of the model). >> >> A trite response might be that, lacking a model, it changes nothing. >> >> But I suspect that what is happening here is, lacking a common model at this >> stage, that we each have our own model which we are using to interpret or think >> about the terms we're trying to describe. >> >>> Leaving out description, which I agree is separable, where do we stand with thing/IVP? >> >> Well, I thought Simon's proposal [1] captured that part quite nicely. >> >> (The term "entity" for was agreed at F2F1 [2] - I always thought that "thing" >> was just another term for entity, but checking the log at [2] I see this is not >> universally held - I never really tuned in to the distinction here.) >> >> [1] http://www.w3.org/2011/prov/wiki/Talk:F2F1ConceptDefinitions#Entity_and_IVP_of >> >> [2] http://www.w3.org/2011/prov/meeting/2011-07-06#Session_2__3a__Model_Task_Force >> >> >>> Thing is being talked about as entity now (and was Bob for a while)? >> >> I think "bob" was never entirely clear - and may well have been the subject of >> multiple interpretations. I for one am not comfortable with the notion of a >> "state" that "bob" >> >>> And the argument is that we don't need to distinguish between the idea of a provenance >>> thing and the entity definitions in other ontologies, or perhaps better - the mapping >>> of instances of the classes 'comet' and 'comet-near-star' to provenance >> entities is not >>> part of the model, but is an implementation detail? >> >> There are several issues in this. Let me try to pick apart: >> >> "we don't need to distinguish between the idea of a provenance thing and the >> entity definitions in other ontologies" - I'm not arguing this - I think a >> distinction *is* needed. >> >> (If you had used entity "description" instead of entity "definition" (implying >> possible arbitrary metadata about an entity), then I'd be less clear cut, but at >> some level I think this group does want to have some notion of provenance from >> other descriptions. My mental model has provenance as a subset of arbitrary >> entity descriptions; I imagine a property like "hasProvenance", which may be a >> subproperty of something like rdfs:seeAlso. As for exactly what constitutes >> provenance information, I think that is somewhat open.) >> >> "the mapping of instances of the classes 'comet' and 'comet-near-star' to >> provenance entities is not part of the model" - I'm having trouble with two >> terms here: "mapping" and "entity". I think we have adopted the term "entity" >> (pro tem, at least) to be roughly "something about which we wish to express >> provenance". I don't know what you mean by "mapping instances" here, but I'm >> guessing something like "relating". In any case, I can't find an interpretation >> of this that I'd agree with. >> >> That is, I think the relationship between entities and provenance *is* part of >> the model, just not part that is covered by Simon's definition. Again, we seem >> to be back to the problems of considering term definitons in isolation. >> >>> How do we know that "Halley's Comet" and "Halley's comet near the sun" >>> are related and not 'representations' of different 'stuff'? >>> ("Kahoutek-near-the-sun" Is not an IVP of/not related to "Halley's comet".) >> >> That's a question of epistemology. In my mental model, we know that if it is >> asserted. We might even define a property for it ... which is what I saw >> Simon's definition edging towards. >> >>> What terms/description of 'representation' and 'stuff' is current? >>> Do we still agree that there is something out there behind/beyond entities? >> >> I understand the current term here is "entity" for anything about which we might >> wish to express provenance. Like a web _resource_, an _entity_ can be >> identified by a URI (but is not required to be). In my mental model, _entities_ >> may be related to each other by a notion like IVP, though I prefer to think of >> that as "contextual constraint" which can be expressed in terms of >> truth-of-assertions. >> >>> Where does IVP stand? >> >> See above for a personal take. >> >>> What I'm picking up for the most part is that IVP can't be hierarchical in general, >>> which I think has faded as we tried to talk about properties of one entity having >>> to be immutable in an IVP of it. Technically, I'm not sure we ever said that >> there >>> couldn't be properties going in the reverse direction >>> (allowing A IVP of B and B IVP of A), and my original arguments were that >>> invariance was relative to the processes being discussed which also implies >>> IVP relationships could go in both directions depending on the processes you >>> wanted to talk about. Is the current discussion just reaffirming that we're not >>> talking about hierarchies of invariance, or is there more to the discussion >>> about how the IVP relationship has to change? >> >> I see IVP being hierarchical, but I do think that it is transitive: >> >> Comet -> Halley's comet -> Halley's comet near sun >> -> comet near sun >> -> Kahoutek -> Kahoutek near sun >> >> (where *all* of the things (sensu colloq.) mentioned above are _entities_) >> >> So we have: >> >> Halley's comet _IVP_ comet >> Kahoutek _IVP_ comet >> Comet near sun _IVP_ comet >> >> Halley's comet near sun _IVP_ Haley's comet >> Halley's comet near sun _IVP_ comet near sun >> Halley's comet near sun _IVP_ comet >> >> Kahoutek near sun _IVP_ Kahoutek >> Kahoutek near sun _IVP_ comet near sun >> Kahoutek near sun _IVP_ comet >> >> But NOT other relations that would be needed if IVP were to be hierarchical. >> >> I'm sorry of all this is a bit laboured, but I hope this helps to clarify my >> understanding. >> >> #g >> -- >> >>>> -----Original Message----- >>>> From: public-prov-wg-request@w3.org [mailto:public-prov-wg- >>>> request@w3.org] On Behalf Of Simon Miles >>>> Sent: Wednesday, July 13, 2011 8:36 AM >>>> To: Provenance Working Group WG >>>> Subject: Re: Models and their use >>>> >>>> Jim, Graham, >>>> >>>> Reading through your comments, I'm pretty much in agreement with them. >>>> The discrepancy between my view and Jim's is, I think, just a matter of what >>>> we assume is being defined at the moment (i.e. by entity/thing). >>>> >>>> As in Graham's last mail, I am assuming that we are first defining any >>>> (contextualised) entity ((1) in Graham's classification). >>>> >>>> I fully agree with you that assertion/observation/description (2) is also an >>>> important and distinct concept. However, I see it as secondary to the idea of >>>> entity in the model and, as Graham says, a description is itself a kind of >>>> entity. This may be comparable to agents or process executions, i.e. agents, >>>> executions and descriptions are all particularly important (for provenance) >>>> subclasses of entity. >>>> >>>> And I think this difference in our views about what was being defined by >>>> "thing" nicely illustrates the original point I was trying to make about the >>>> conflation in the definition :-) >>>> >>>> Thanks, >>>> Simon >>>> >>>> On 13 July 2011 11:01, Graham Klyne <GK@ninebynine.org> wrote: >>>>> Jim, >>>>> >>>>> I've been thinking about your comments, and have come to a view that >>>>> there are two things going on here, which are not being clearly >>>> distinguished: >>>>> 1. an entity constrained to some context >>>>> >>>>> 2. observations or descriptions of an entity >>>>> >>>>> which when combined can model observations/descriptions of an entity >>>>> constrained to some context. I have been focusing on (1), with the >>>>> expectation that (2) would be dealt with separately in the model, >>>>> where provenance is a kind of description. If I understand correctly, >>>>> you are particularly concerned to distinguish between entity and >>>>> description. It seems to me that "bob" has been adopted variously to fulfil >>>> both these distinctions. >>>>> ... >>>>> >>>>> Example: suppose we're interested in Halley's comet, and in particular >>>>> in the periods when it is close to the sun or visible from earth. So >>>>> we have two >>>>> concepts: Halley's comet and Halleys comet when close to Earth. To >>>>> my mind, these are both *entities* (sensu F2F1). Any description that >>>>> is true of Halley's comet generally should also be true of it when >>>>> close to Earth, but there are many other assertions are true the >>>>> constrained Halley's comet that are probably not true at all times >>>>> (e.g. the appearance of a tail due to expulsion of gas and dust caused by >>>> solar heating). >>>>> The page http://en.wikipedia.org/wiki/Halley's_Comet is a >>>>> *description* of Halley's comet. Being a Wikipedia page, it probably >>>>> changes over time. So we may wish to discuss it as it exists in a >>>>> particular period of time. Today, for example, it contains a list of >>>>> 95 references indicating sources of information used in the page. >>>>> Thus we may expect this page to be a description of Halley's comet for >>>>> its entire lifetime, but needs to be constrained to make statements >>>>> about the number of references it contains. In this respect, the page is >>>> both an "entity" and a "description" of an entity. >>>>> The page at http://en.wikipedia.org/wiki/Halley's_Comet also has a >>>>> brief description of a Cuneiform-inscribed clay tablet which is both >>>>> an entity in its own right, with its own description and provenance, >>>>> *and* a record of observation of Halley's comet. I don't think we can >>>>> easily disjoin the class of descriptions from the class of entities. >>>>> >>>>> Thus, I perceive that the notion of constraint so that some aspects of >>>>> a constrained entity are invariant needs to be dealt with separately >>>>> from the notion of description, which often (but not always, I think) >>>>> applies to a constrained form of some entity. >>>>> >>>>> Does this make any sense? >>>>> >>>>> #g >>>>> -- >>>>> >>>>> >>>>> Jim McCusker wrote: >>>>>> My issue is more with Simon's desire to conflate things with the >>>>>> descriptions of those things. We need to be able to say "x, as >>>>>> described by y", which is a separate issue from relating "x1" as an >>>>>> invariant view of "x2". >>>>>> >>>>>> "x as described by y" can be done in semweb using a URI for X and the >>>>>> URI for a named graph or graph literal for y, assuming that there are >>>>>> assertions in y about x. Another alternative is that y can be >>>>>> discussed as an information artifact, as in the Information Artifact >>>>>> Ontology (http://code.google.com/p/information-artifact-ontology). >>>>>> Since x changes over time, we need something that nails down what was >>>>>> actually "seen", or at least, claimed when the agent identified x in >>>>>> its context. >>>>>> >>>>>> A BOB is the y in the above paragraph, and I think that the fact that >>>>>> it's something that's describing an x, it must have the extra >>>>>> qualification in place in its name. >>>>>> >>>>>> Jim >>>>>> >>>>>> On Tue, Jul 12, 2011 at 3:27 PM, Graham Klyne <GK@ninebynine.org> >>>> wrote: >>>>>>> [Off-list] >>>>>>> >>>>>>> Jim, >>>>>>> >>>>>>> I had some small reservations about Simon's definition, but I felt >>>>>>> that it was such a big improvement over what we currently have that >>>>>>> I didn't want to muddy the waters just yet by adding qualifications >>>>>>> to my support :) >>>>>>> >>>>>>> (Specifically, I would remove "and something more is invariant about >>>>>>> B" from the efinition of invariant view, so that anything can be an >>>>>>> invariant view of itself (or not excluded from so being) - which I >>>>>>> think is one of the concerns you raised.) >>>>>>> >>>>>>> Apart from that, I think there is an aspect of an invariant view >>>>>>> that is in some sense fundamentally subsumptive -- there is a >>>>>>> distinct sense that A and B are generally the same, except that one may >>>> be more constrained. >>>>>>> But, more importantly, I think we need to be looking to say less, not >>>> more. >>>>>>> I feel that Simon's definition captures close to what we need to say >>>>>>> without adding too much more. >>>>>>> >>>>>>> In this, I'm arguing for the minimum useful semantics - it's easier >>>>>>> to add (or layer) constraints later than to remove them from an >>>>>>> established defintion. By providing a little as we can for people >>>>>>> to disagree with, I think we maximize the potential for take-up of the >>>> WG outputs. >>>>>>> #g >>>>>>> -- >>>>>>> >>>>>>> >>>>>>> Jim McCusker wrote: >>>>>>>> On Tue, Jul 12, 2011 at 12:02 PM, Graham Klyne <GK@ninebynine.org> >>>> wrote: >>>>>>>>> Simon Miles wrote: >>>>>>>>>> To understand the consequences of the above points, I suggest >>>>>>>>>> alternative definitions at the link below: >>>>>>>>>> >>>>>>>>>> >>>>>>>>>> >>>> http://www.w3.org/2011/prov/wiki/Talk:F2F1ConceptDefinitions#Enti >>>>>>>>>> ty_and_IVP_of >>>>>>>>> +1 >>>>>>>>> >>>>>>>>> I think this is a big improvement over what we have. >>>>>>>> I like the Entity definition, but I'm not sure how we then go about >>>>>>>> qualifying assertions about Entities. We need a way of making those >>>>>>>> assertions (which is what BOBs were for) and a way of relating >>>>>>>> Entities that are the same, even if they aren't mathematically the >>>>>>>> same (different state, different aspect, etc.). IVP of as it's >>>>>>>> defined there is not quite enough, since it only allows for >>>>>>>> relations between entities that have subsumptive (a is IVP of b, >>>>>>>> therefore a has all the states of b plus some). >>>>>>>> >>>>>>>> Jim >>>>>>>> -- >>>>>>>> Jim McCusker >>>>>>>> Programmer Analyst >>>>>>>> Krauthammer Lab, Pathology Informatics Yale School of Medicine >>>>>>>> james.mccusker@yale.edu | (203) 785-6330 >>>>>>>> http://krauthammerlab.med.yale.edu >>>>>>>> >>>>>>>> PhD Student >>>>>>>> Tetherless World Constellation >>>>>>>> Rensselaer Polytechnic Institute >>>>>>>> mccusj@cs.rpi.edu >>>>>>>> http://tw.rpi.edu >>>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> __________________________________________________________ >>>> ____________ >>>>> This email has been scanned by the MessageLabs Email Security System. >>>>> For more information please visit http://www.messagelabs.com/email >>>>> >>>> __________________________________________________________ >>>> ____________ >>>> >>>> >>>> -- >>>> Dr Simon Miles >>>> Lecturer, Department of Informatics >>>> Kings College London, WC2R 2LS, UK >>>> +44 (0)20 7848 1166 >>> >>> >>> >> >> > > ______________________________________________________________________ > This email has been scanned by the MessageLabs Email Security System. > For more information please visit http://www.messagelabs.com/email > ______________________________________________________________________ > -- Dr Simon Miles Lecturer, Department of Informatics Kings College London, WC2R 2LS, UK +44 (0)20 7848 1166
Received on Thursday, 14 July 2011 10:26:35 UTC