RE: PROV-ISSUE-8: defining generation in terms of `IVPT of'

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 17:14:56 UTC