- From: Luc Moreau <L.Moreau@ecs.soton.ac.uk>
- Date: Fri, 10 Jun 2011 22:07:39 +0000
- To: "Myers, Jim" <MYERSJ4@rpi.edu>
- CC: "public-prov-wg@w3c.org" <public-prov-wg@w3c.org>
On 10 Jun 2011, at 21:02, "Myers, Jim" <MYERSJ4@rpi.edu> wrote: >> >> In this definition, you say when X didn't exist(before P) but you > don't say >> when it starts to exist. Is it intended? > > I updated the wiki as follows: > * X did not exist before P began, > * X began to exist sometime before P ended, and > * X would not have begun existing if P had not occurred/P was necessary > for X's existence to happen. Doesn't this say X began to exist between the start and end of P? Luc > >> >> Also, did you really mean before P began? Can you explain why ? > > If X is generated by P, it can't have existed before P did. I think this > is just saying P must start before the creation of X if X is generated > by P. > > Is it a matter of wording or is something mixed up logically? >> >> Can X change, i don't understand what happens then? Does the last > condition >> necessarily apply? > > The generated thing/resource X can change after being generated, but > only in ways consistent with its definition/type. An egg (defined as an > ovoid object produced by a chicken) generated by a chicken can > participate in boiling and painting (but I can't say what color such an > egg is since color is not part of the definition of what makes one > instance of the egg class unique/identifiable.) Other definitions of egg > (IVPTs of each other) differ in how mutable they are. If you want a > fairly immutable concept of egg, define it as a ovoid product of a > chicken that has a particular color, is cooked/uncooked, > cracked/uncracked, etc. Then we can talk about the Easter Egg that was > derived from the uncooked/uncolored egg from a particular chicken > through a series of processes. (Or, we could just say that after being > generated, the egg sat and at some point we recognized that it existed > in a state that corresponds to our notion of Easter egg and we assert > that EasterEgg Y is an IVPT of egg X.) > > Does the last condition apply? - Is that "must there always be a Y that > X is an IVPT of"? I don't know, but I suspect the answer is yes in any > practical sense. By the IVPT definition I posted, all I need is some > process P that would destroy/consume X and define Y as "X considered > mutable with respect to P" - "the idea of this egg that would be > unaffected even by the end of the universe" or some such might be the > end of the line though. >> >> Are you also saying there needs to be another notion? Modification? > > I think the other notion is some form of participation (also uploaded > definitions there). I was saying participates in/is modified by for the > thing/process relationship. (Agency/control would be one form of > participation). The egg layed by the chicken participates in boiling and > coloring during its lifetime. It is not modified in the sense that any > part of what identifies it changes, but attributes of it we consider > transient (can't be used to discover this egg reliably because they > change) do change. > > -- Jim > > >> >> Professor Luc Moreau >> Electronics and Computer Science >> University of Southampton >> Southampton SO17 1BJ >> United Kingdom >> >> On 10 Jun 2011, at 18:14, "Myers, Jim" <MYERSJ4@rpi.edu> wrote: >> >>> Posted on the wiki - basically the same definition as from Jun and >>> Daniel with more discussion of how the IVPT concept and the idea of >>> modifiable objects relate. >>> -- Jim >>> >>>> -----Original Message----- >>>> From: Luc Moreau [mailto:L.Moreau@ecs.soton.ac.uk] >>>> Sent: Friday, June 10, 2011 12:57 PM >>>> To: Myers, Jim >>>> Cc: public-prov-wg@w3c.org >>>> Subject: Re: PROV-ISSUE-8: defining generation in terms of `IVPT > of' >>>> >>>> Jim and all, >>>> >>>> Could you put forward a revised definition that addresses better > your >>>> concerns? >>>> >>>> Professor Luc Moreau >>>> Electronics and Computer Science >>>> University of Southampton >>>> Southampton SO17 1BJ >>>> United Kingdom >>>> >>>> >>>> On 10 Jun 2011, at 17:51, "Myers, Jim" <MYERSJ4@rpi.edu> wrote: >>>> >>>>> >>>>>> >>>>>> Hi Jim >>>>>> I think we are discussing two issues here. >>>>>> >>>>>> 1. You suggest that the egg is itself an IVPT. >>>>>> >>>>>> There are different ways of looking at this: >>>>>> a. I was saying that an egg was a thing (identified, and typed >>>>> according to >>>>>> an ontology) >>>>>> Then, it's a question of choice of a same ontology, or >>>>> ontology >>>>>> refinement, a classical problem, >>>>>> which we will not solve here. >>>>> >>>>> I would claim the things in IVPT relationships with egg are also >>>>> things that can be identified, typed, etc., not necessarily in the >>>>> same class or ontology as 'egg'. (A logical picture is not the > same >>>>> class of thing as a jpg file corresponding to a particular >>>>> manifestation of that image). >>>>> >>>>>> >>>>>> b. We could say that there is in an alternate account, which >>>>> describes the >>>>>> egg in terms of molecules. >>>>> >>>>> Yes - my object in that account is 'set of molecules' and 'egg' is > a >>>>> convenient label for when those molecules are in a particular > subset >>>>> of all the configurations they can be in. If you say egg is an >>> object >>>>> and require a different type of thing to be used to describe > things >>>>> that invariant views of my set of molecules, I can't use it in my >>>>> account, and we don't yet have any mechanism to make it clear that >>>>> somehow my 'state of set of molecules' corresponds to your notion > of >>> 'egg'. >>>>> >>>>>> >>>>>> c. Alternatively, we have IVPTs of IVPTs of IVPTs ... >>>>>> is there a base case? I fear we are going to reach quantum >>>>> mechanics ... >>>>> >>>>> I don't think we have to be afraid of this - and I would rephrase >>> and >>>>> say we have things of different types that can be in IVPT >>>>> relationships with each other and your concern is then whether the >>>>> fact that we can make deep hierarchies is an issue. I'd answer > that >>> by >>>>> saying that the base case is in the middle - things like eggs are >>>>> useful not because they are somehow true objects where other > things >>>>> are just views, they are useful views because of the > natural/common >>>>> processes they participate in. The fact that the model allows one > to >>>>> describe a set of quantum wave functions and claim one view of > them >>> is >>>>> an egg doesn't mean that this will happen in practice (though > there >>>>> are scientists who do essentially this on a daily basis at the >>> nano-scale). >>>>> >>>>> Whether it is truly 'turtles all the way down' is a philosophical >>>>> question I'm not sure we have to answer - modeling it that way >>> covers >>>>> the middle ground without requiring any connection to real base >>>>> objects (or more neutrally, without identifying a particular set > of >>>>> objects as real with all others some form of constructed view) - > in >>>>> this sense, I would ask you a) whether you see a >>>>> consequence/limitation of a model that does not define which > objects >>>>> are 'real'? and b) given the debates about ontologies in the > world, >>> do >>>>> you think we can reach a consensus on what the base reality is? >>>>> >>>>> >>>>>> >>>>>> 2. You are commenting on the word modified. >>>>>> If I crack the egg, >>>>>> Y-> crack -> X >>>>>> Y and X are IVPTs of egg >>>>>> Y->X (we have a derivation) >>>>>> >>>>>> So looking at generation only, I feel it's OK to say the egg >>> is >>>>> modified, since >>>>>> we >>>>>> have now a new IVPT Y about the same egg. >>>>>> >>>>>> So, could you maybe make some suggestions on how you would revise >>> the >>>>>> definition? >>>>> >>>>> I'm not sure what point you're making about the cracking example, >>> but >>>>> I'd say generation is just a case where we are more >>>>> familiar/comfortable with the thing produced by a process > execution >>> as >>>>> a useful thing to discuss/track the provenance of, and potentially >>>>> where the inputs of the process execution are uninteresting. A >>> chicken >>>>> lays an egg not because we can't talk about a set of atoms that > the >>>>> chicken rearranges into a state we want to identify as an egg but >>>>> because that view is not very useful, so identifying the 'set of >>> atoms >>>>> in the chicken' that is used to produce the egg or the 'set of >>> atoms' >>>>> that exists before and after egg laying that comprise the egg > after >>>>> laying isn't useful and we record chicken controls eggLaying which >>>>> generates egg. Both/all variant accounts are valid and consistent > in >>>>> the model I'm advocating, specifically egg does not change type > from >>>>> being a real object to a state of a set of atoms - 'set of atoms' > is >>> a >>>>> real thing that has a stateful view corresponding to a real thing >>>>> called an egg (an IVPT relation with egg). The fact that 99+% of > us >>>>> would just report generation of an egg and stop is OK (good in > fact >>> - >>>>> we don't want to needlessly talk about alternate views any more > than >>>>> we should feel pressure to expand all processes into fine grained >>>>> steps or include info about the movement of electrons in > describing >>>> computations). >>>>> >>>>> Thanks, >>>>> >>>>> Jim >>>>>> >>>>>> Thanks, >>>>>> Luc >>>>>> >>>>>> >>>>>> On 06/10/2011 02:28 PM, Myers, Jim wrote: >>>>>>> >>>>>>> >>>>>>>> -----Original Message----- >>>>>>>> From: Luc Moreau [mailto:L.Moreau@ecs.soton.ac.uk] >>>>>>>> Sent: Friday, June 10, 2011 3:26 AM >>>>>>>> To: Myers, Jim >>>>>>>> Cc: public-prov-wg@w3c.org >>>>>>>> Subject: Re: PROV-ISSUE-8: defining generation in terms of > `IVPT >>>>> of' >>>>>>>> >>>>>>>> Hi Jim, >>>>>>>> >>>>>>>> I had not seen your comment in line, my responses are also >>> inline. >>>>>>>> >>>>>>>> On 10/06/11 02:28, Myers, Jim wrote: >>>>>>>> >>>>>>>>> This would mean that a heating process modifies an egg to > create >>> a >>>>>>>>> >>>>>>> warm egg, >>>>>>> >>>>>>>> it does not transform a cold egg into a warm egg? >>>>>>>> >>>>>>>>> Or do you mean both - a process execution can turn one thing >>> into >>>>>>>>> >>>>>>> another, >>>>>>> >>>>>>>> these things can be considered IVPTs of a thing that > participates >>>>> in >>>>>>>> >>>>>>> the process >>>>>>> >>>>>>>> execution/ is modified by the process execution? And in an open >>>>> world >>>>>>>> assumption, a witness doesn't have to report the modified thing >>> or >>>>>>>> can >>>>>>>> >>>>>>> decline >>>>>>> >>>>>>>> to identify/report either of things in IVPT roles depending on >>>>> their >>>>>>>> >>>>>>> ability to >>>>>>> >>>>>>>> observe and the use case they wish to enable? >>>>>>>> >>>>>>>>> ________________________________ >>>>>>>>> >>>>>>>>> From: public-prov-wg-request@w3.org on behalf of Luc Moreau >>>>>>>>> Sent: Thu 6/9/2011 6:44 PM >>>>>>>>> To: Provenance Working Group WG >>>>>>>>> Subject: PROV-ISSUE-8: defining generation in terms of `IVPT > of' >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Hi all, >>>>>>>>> >>>>>>>>> - if a new thing is created, it is clear that we have a new > IVPT >>>>> of >>>>>>>>> that thing >>>>>>>>> >>>>>>>>> if a chicken creates an egg is it just an IVPT of an egg? >>>>>>>>> >>>>>>>>> >>>>>>>> I would think the physical object is the egg. >>>>>>>> I thought we had agreed that for a provenance purpose, we had > to >>>>> talk >>>>>>>> >>>>>>> about >>>>>>> >>>>>>>> an IVPT of that egg. >>>>>>>> >>>>>>> But 'the egg' is also an IVPT of the stuff that goes into the > cake >>> - >>>>> a >>>>>>> temporary 'state' in which yolk and white are together and not >>>>>>> mixed/chemically altered, etc. >>>>>>> >>>>>>>> >>>>>>>>> - if the thing is modified, then it is a requirement that a > new >>>>> view >>>>>>>>> >>>>>>> (IVPT) is >>>>>>> >>>>>>>> generated ... >>>>>>>> >>>>>>>>> otherwise, it would still be a view that existed before >>>>>>>>> >>>>>>>>> can't I say the egg was heated without reporting its cold and >>> warm >>>>>>>>> >>>>>>> states? I.e. >>>>>>> >>>>>>>> don't we want to be able to report that something was modified >>>>>>>> without >>>>>>>> >>>>>>> having >>>>>>> >>>>>>>> to report the IVPTs? A document was edited four times by >>> different >>>>>>>> >>>>>>> people but I >>>>>>> >>>>>>>> don't wan't to/can't tell you what each wrote at each stage? >>>>>>>> >>>>>>>>> >>>>>>>> These comments were made in the context of defining Generation > of >>>>> an >>>>>>>> >>>>>>> IVPT. >>>>>>> >>>>>>> OK - but you said "if the thing is modified"... For generation, > I >>>>>>> would say the chicken participates in an egg laying process >>>>> execution >>>>>>> that generates an 'egg'. That 'egg' is an IVPT of the chemicals > in >>>>> it >>>>>>> (which existed before). The 'egg' can also have further/more >>>>> stateful >>>>>>> IVPTs that are more useful for discussing heating, cracking, > etc. >>>>> The >>>>>>> sense in which generation is special is that it is a derivation >>> from >>>>>>> things we don't consider logically an aspect/IVPT of something >>>>>>> greater. I.e. the 'mass of egg-bound chemicals' in the chicken >>> just >>>>>>> changes its state to become the 'egg', nothing really appears or >>>>>>> disappears (conservation of mass and energy). Unless/until a >>>>> scientist >>>>>>> wants to look at the potential for different processing of >>> chemicals >>>>>>> going into the egg versus those used to build the chicken's own >>>>> body, >>>>>>> 'mass of egg-bound chemicals' isn't something we'd usually think >>>>>>> about, but it's a valid perspective and consistent with the view >>> of >>>>> an >>>>>>> egg being generated (both views can be drawn on the same graph > in >>>>> the >>>>>> way I've been describing). >>>>>>> >>>>>>> >>>>>>>> The document was edited four times could be expressed by 4 >>> process >>>>>>>> >>>>>>> execution >>>>>>> >>>>>>>> and something like opm:wasTriggeredBy in between. >>>>>>>> >>>>>>>> >>>>>>>>> - if the process execution was taking a long time to >>> modify/create >>>>>>>>> >>>>>>> the thing, >>>>>>> >>>>>>>> there is only one >>>>>>>> >>>>>>>>> instant at which the (invariant!) IVPT appears >>>>>>>>> >>>>>>>>> I thnk we could define it that way, but if a cracking process >>>>> takes >>>>>>>>> >>>>>>> time, saying >>>>>>> >>>>>>>> the cracked egg appears instantaneously basically means you > want >>>>>>>> >>>>>>> 'cracked egg' >>>>>>> >>>>>>>> to be defined by some threshold - the cracked egg might become >>> more >>>>>>>> >>>>>>> cracked >>>>>>> >>>>>>>> over time ) invariant only in that it is always above the >>> threshold >>>>>>>> >>>>>>> and the >>>>>>> >>>>>>>> instance of the creation of the IVPT relationship occurs ata >>>>>>>> >>>>>>> aspecific instant. >>>>>>> >>>>>>>>> >>>>>>>> Yes, agreed. >>>>>>>> >>>>>>>> >>>>>>>>> - I think this captures well a stateful objects, where > processes >>>>> can >>>>>>>>> >>>>>>> modify the >>>>>>> >>>>>>>> object, resulting in >>>>>>>> >>>>>>>>> different IVPTs corresponding to the various states >>>>>>>>> >>>>>>>>> IVPTs are not a separate kind of thing and their invariance is >>>>>>>>> >>>>>>> relative. If they >>>>>>> >>>>>>>> are truly immutable sates/snapshopts, they can only exist for > an >>>>>>>> >>>>>>> instant because >>>>>>> >>>>>>>> some part of the state of the thing (a part we may not care > about >>>>>>>> such >>>>>>>> >>>>>>> as age) >>>>>>> >>>>>>>> will change immediately. >>>>>>>> >>>>>>>>> >>>>>>>> I am not sure I agree, here. IVPTs are a view/perspective on a >>>>> thing. >>>>>>>> >>>>>>> Perhaps I should argue from the other direction - the notion of > a >>>>>>> thing is also a perspective/view. "eggs" don't exist - only >>>>> temporary >>>>>>> co-locations of particular molecules. Galton and Mizoguchi's > paper >>>>>>> argues that objects are defined by what processes you consider > to >>> be >>>>>>> internal to and external to the object - if you change the set > of >>>>>>> processes you are concerned about, you describe the world using >>>>>>> different objects. In this sense, eggs feel more 'real' because >>> the >>>>>>> set of processes we see happening frequently to them preserve >>>>> aspects >>>>>>> of their state, so egg as an IVPT is useful/predictive/etc. >>>>>>> >>>>>>>> Alternative views asserted by other asserters may co-exit. >>>>>>>> - it's a decaying egg >>>>>>>> - it's a duck egg, not a hen egg >>>>>>>> - it's a chocolate egg >>>>>>>> >>>>>>>> >>>>>>> I agree, so again from the other direction - I don't see why > 'egg' >>>>> is >>>>>>> more real/more correct/more special than any of these, they're > all >>>>>>> IVPTs. >>>>>>> >>>>>>> >>>>>>>> It is a requirement of any specific perspective to be > invariant. >>>>>>>> >>>>>>> Invariant relative to a view in which only certain processes are >>> of >>>>>>> interest (are observable/reported?). >>>>>>> >>>>>>> >>>>>>>> So, it's not a snapshot of the global egg state, but it's a >>>>> snapshot >>>>>>>> >>>>>>> according to a >>>>>>> >>>>>>>> view. >>>>>>>> >>>>>>>> An analogy would be several cameras pointing to a same egg. >>>>>>>> From one camera, the egg is still, no change occurring. >>>>>>>> From the other, we see a crack appearing. >>>>>>>> So one asserter can describe change in a physical object, while >>>>>>>> >>>>>>> another does not >>>>>>> >>>>>>>> describe any change. >>>>>>>> But it's the same egg. >>>>>>>> >>>>>>> Right - those are two views of something. But that something is >>> just >>>>>>> another view - one camera sees a soup of chemicals that are >>> swirling >>>>>>> and mixing (slowly for an egg) while another sees one thing (the >>>>> egg). >>>>>>> Both of these are just IVPTs too. The chemical view is mutable > by >>>>> more >>>>>>> processes than the egg view, but it is more persistent (it lasts >>>>>>> longer because we've defined it in a way that the processes that >>> can >>>>>>> create/destroy it are less frequent). >>>>>>> >>>>>>> I know that thinking of everything as an IVPT is not necessarily >>>>>>> intuitive, and that one can argue that it is just one way to > model >>>>> the >>>>>>> world/a philosophy, but I think it is a model that has the right >>>>>>> conceptual power to deal with the use cases we have (and the >>> general >>>>>>> set we can envision) while also being one that, in practice, > will >>>>> fade >>>>>>> away >>>>>>> - most people will agree that 'egg' and not 'mass of chemicals' > is >>> a >>>>>>> more useful IVPT to talk about and we'll see 'eggs' used in cake >>>>>>> baking and the world will mostly look like OPM (straight >>>>>>> thing-execution-thing chains), but we'll still have the power to >>>>> drop >>>>>>> down and talk about cracking or go up and talk about > conservation >>> of >>>>> mass >>>>>> when needed. >>>>>>> >>>>>>> I also don't know what a coherent alternative is that, once we > add >>>>> in >>>>>>> all the features necessary to cover the use cases, we'll like >>>>> better. >>>>>>> There are certainly other ways to model - my question really is >>>>>>> whether there are others that will end up being more intuitive >>> once >>>>>>> all the needed features are dropped in. >>>>>>> >>>>>>> -- Jim >>>>>>> >>>>>>> Jim >>>>>>> >>>>>>>> Luc >>>>>>>> >>>>>>>>> What do you think? >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>> >>>> >> http://www.w3.org/2011/prov/wiki/ConceptGeneration#Definition_of_Gene >>>>>>>> r >>>>>>>> >>>>>>>>> ation_by_Luc >>>>>>>>> >>>>>>>>> Cheers, >>>>>>>>> Luc >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>> >>>>>> -- >>>>>> Professor Luc Moreau >>>>>> Electronics and Computer Science tel: +44 23 8059 4487 >>>>>> University of Southampton fax: +44 23 8059 2865 >>>>>> Southampton SO17 1BJ email: > l.moreau@ecs.soton.ac.uk >>>>>> United Kingdom > http://www.ecs.soton.ac.uk/~lavm >>>>>
Received on Friday, 10 June 2011 22:08:32 UTC