Re: PROV-ISSUE-67 (single-execution): Why is there a difference in what is represented by one vs multiple executions? [Conceptual Model]

Simon,

Finding a neutral term for 'cannot infer derivation across' that could be an annotation on a Bob or a PE would be fine ... just a neutral assertion without further explanation.

Having to make a relationship 'isNotDerivedFrom' between any/every two Bobs would be similar - would also work - but may be more work - I guess it depends on which use case is more common - are there a lot of processes where all/many of the input/output pairs are not connected? I guess I'd prefer the 'cannotinferderivationacross' option as a way to make a neutral statement - partly as a guess about what the common case is and because 'isNotDerivedFrom' opens another door - there's no derivation for entirely separate things either (rhino notderivedfrom ship) and having both positive and negative assertions gets messy.

Jim

> -----Original Message-----
> From: public-prov-wg-request@w3.org [mailto:public-prov-wg-
> request@w3.org] On Behalf Of Simon Miles
> Sent: Friday, August 05, 2011 10:49 AM
> To: Provenance Working Group WG
> Subject: [Spam:***** SpamScore] Re: PROV-ISSUE-67 (single-execution): Why
> is there a difference in what is represented by one vs multiple executions?
> [Conceptual Model]
> 
> Hi Jim,
> 
> I like your proposal, and agree the definition of isDerivedFrom seems to
> capture the essential meaning of derivation independent of accounts.
> 
> It would be great if it is possible for the first draft of the model to make sense
> without any implicit idea of accounts, so that we could leave discussion of what
> they mean until later.
> 
> >From a perspective of keeping the proposal simple, I wonder if we lose
> much by, rather than labelling PEs or entities/bobs as 'composite', just having a
> 'isNotDerivedFrom' assertion. If you want to express the reason why B is not
> derived from A, you just give a finer granularity graph.
> 
> Thanks,
> Simon
> 
> On 5 August 2011 15:30, Myers, Jim <MYERSJ4@rpi.edu> wrote:
> > An account -dependent definition of derivation would be much less
> > useful. Let me try to restate what I've been saying as a proposal that
> > I think will capture our collective sense of derivation and that will
> > lead to some clear consequences for the model.
> >
> >
> >
> > Derivation means that, independent of the granularity of the
> > description of provenance there exists (assuming the description is
> > complete) a chain of used-PE-generated relationships between the two
> > entities. That is B isDerivedFromA if there is a direct, directed,
> > linear path between them (no breaks, no temporal zig-zags).
> >
> > A <---PE.1 <---X <---PE.2<---Y<---PE.3<----B - derivation
> >
> > A<--------PE.1
> >             /
> >          X
> >        /
> >      PE.2<---B - no derivation, though in some account A<---PE<---B
> > (with used occurring after generation)
> >
> > A<---PE1<-----X.1
> >                        \
> >                         PE2
> >                           \
> >                            X.2<--PE3<---B - derivation
> >
> > A <----PE1 <--- X.1
> >
> >                        X.2<---PE2<----B - no derivation, though in
> > some account A<---PE1<---X<---PE2<---B (with no processes internal to
> > X such that one part influences the other)
> >
> >
> > The idea of this is consistent with our discussions - if A was used
> > after B was generated, there is no such path between them and an
> > account with finer granularity of the PE could show it to be multiple
> > subprocesses with A used by one that occurs after the one that
> > generates B (there's no path, or the path has one or more links in the
> > opposite temporal direction. The part/attribute cases also fit - going
> > to finer granularity would show there's no such path.
> >
> > The consequences of this definition are that, without additional
> > information (which we may want to add in the model - see below),
> > derivation cannot be derived from a used-PE-generated structure in a
> > given account, and derivation is not transitive.
> >
> > Since we have groups and use cases where either or both of these would
> > be useful, we can ask what else is needed to allow them:
> >
> > To allow derivation to be inferable, we need to know the connectivity
> > inside a PE. For a PE with m inputs and n outputs, this is an n x m
> > matrix if we want full detail, but it may be sufficient for most cases
> > to simply label the PE as fully connected or not. I would be inclined
> > to make the default 'fully connected' and to allow a PE to be tagged
> > as 'less-than-fully-connected'/'composite'/'decomposable' to stop
> > inferencing about derivation. I think this default would be a good
> > 80-90% solution while also allowing users/asserters to rigorously
> > indicate when inference is not appropriate. Asserters would always be
> > able to directly assert derivation and/or decompose partially
> > connected PEs to allow the inferences that are valid while still
> > indicating which ones are not.
> >
> > A similar mechanism would apply for Bobs and allow transitivity for
> > derivation - A Bob that is fully connected - it is either one thing,
> > or the parts of the thing interact (there are internal processes in B
> > that if expanded would show that there is a path from C to A) - is
> > sufficient to support transitivity. Again, I would argue that the
> > default might be 'fully-connected' since that is likely to be the most
> > popular case, and one could label a Bob as 'composite'/'not well
> > mixed'/'not fully integrated'/'decomposable' to stop transitivity.
> >
> > The benefits of this proposal are that I think it really captures the
> > essence of what we all think of as derivation in a rigorous way that
> > is not asserter/account dependent. It also focuses directly on the
> > provenance graph versus trying to relate attributes of Bobs or the
> > nature (as described in a recipe) of a PE.
> >
> > Choosing the defaults to be fully connected would open the door for
> > incorrect assumptions given an open world - if you're missing the
> > 'composite' label on a PE or Bob, you may infer derivation where there
> > isn't any - these defaults would return the largest potential set of
> > derivations given current knowledge. I suspect that this is actually
> > the right way to 'err' - I'd rather have false positives than to flip
> > the situation and be unable to find everything that something truly
> > was derived from. If one inferred a derivation that looked odd, one
> > would simply walk the chain of Bobs and PEs to see if there's evidence
> > that one or more of them might not be fully connected (i.e. one could
> > look in other accounts) along with checking to see if one or more of
> > the provenance statements is simply wrong (A was not an input!).
> >
> > I think one can define a useful equivalent for the distinction between
> > isDerivedFrom and isDerivedFromMultipleSteps as we're talking about
> > them today. I would suggest an account-dependent
> > isDirectlyDerivedFrom(x,y, account z) relationship that would be
> > limited to one hop in a specified account. This would really just be a
> > convenience for scoping a query then and it would have a clear relationship
> to isDerivedFrom.
> > isDirectlyDerivedFrom could be asserted and/or inferred  from a single
> > used-PE-generated structure (same definition as above). isDerivedFrom
> > is always inferable from isDirectlyDerivedFrom). (Both the assertion
> > and inference of isDirectlyDerivedFrom are account dependent, but the
> > dependency is just about the "Direct" part - it would always be true
> > in any account that if you have an isDirectlyDerivedFrom relationship
> > in one account, there is an isDerivedFrom relationship between the
> > same entities that is account-independent). A consequence is that
> > isDerivedFrom would just be the superset of  isDirectlyDerivedFrom and
> > the additional relationships one gets from transitivity. If the
> > asserters view of granularity fits yours, isDirectlyDerivedFrom would
> > give you a useful subset of the overall derivation graph. If not, you
> > just look directly at isDerivedFrom.
> >
> >
> > Cheers,
> >  Jim
> >
> >> -----Original Message-----
> >> From: public-prov-wg-request@w3.org [mailto:public-prov-wg-
> >> request@w3.org] On Behalf Of Luc Moreau
> >> Sent: Friday, August 05, 2011 2:52 AM
> >> To: public-prov-wg@w3.org
> >> Subject: [Spam:****** SpamScore] Re: PROV-ISSUE-67 (single-execution):
> > Why
> >> is there a difference in what is represented by one vs multiple
> > executions?
> >> [Conceptual Model]
> >>
> >> Hi Simon,
> >>
> >> Your proposal is broadly inline with what I am currently drafting.
> >>
> >> Thanks for the name suggestion, which I will shamelessly borrow ;-)
> >>
> >> It is unclear to me at this stage, whether the first definition of
> > derivation is
> >> dependent on account or not, but I made an explicit note about it in
> > the draft
> >> document.  This will have to be discussed again in the next iteration.
> >>
> >> Luc
> >>
> >>
> >> On 04/08/11 18:12, Simon Miles wrote:
> >> > Hi Luc,
> >> >
> >> > OK. I believe that the current definitions do not fully capture
> >> > what I've understood from your mails, so if I was clarifying the
> >> > document based on my current understanding, I would start by
> >> > refining the definitions (and rearranging the existing text to fit):
> >> >
> >> > "That characterized thing B _is derived from_ another characterized
> >> > thing A means that B is transformed from, created from, or affected
> > by
> >> > A. In particular, this means that the values of some attributes of
> >> > B are at least partially determined by the values of some
> >> > attributes
> > of
> >> > A.
> >> >
> >> > xxx (B, A) represents that B is derived from A, and if P is the
> >> > process execution generating B by the account in which the
> > derivation
> >> > is asserted, then P is the execution which used A and derived B
> >> > from it.
> >> >
> >> > yyy (B, A) represents that B is derived from A, by any means
> >> > whether direct or convoluted, and regardless of any other assertion made.
> >> >
> >> > For the account in which yyy (A, B) is asserted to be consistent
> > then,
> >> > within that account, it is implied that either xxx (A, B) also
> >> > holds or there are multiple process executions ultimately using B
> >> > and generating A through a chain of use and generation relations."
> >> >
> >> > xxx is currently called isDerivedFrom and yyy is called
> >> > isDerivedFromInMultipleSteps.
> >> >
> >> > I fear that xxx is impossible to understand properly without
> > including
> >> > accounts, and consistency within accounts, in the model. Once we
> >> > introduce accounts, it then makes sense.
> >> >
> >> > Assuming we don't want to introduce accounts into the current
> >> > draft,
> > I
> >> > propose something like the following:
> >> >
> >> >   - isDerivedFromInMultipleSteps (yyy) is renamed
> > isEventuallyDerivedFrom
> >> >   - isEventuallyDerivedFrom is defined as for yyy above, removing
> > the
> >> > paragraph below mentioning accounts until accounts are introduced
> >> >   - isDerivedFrom (xxx) is excluded from the model until accounts
> > are
> >> introduced
> >> >   - isDerivedFrom+ is also excluded until accounts are introduced,
> > as
> >> > it depends on isDerivedFrom
> >> >
> >> > I don't like the proposal as it removes isDerivedFrom, but I can't
> > see
> >> > how we can define isDerivedFrom in a way which reflects your
> > intention
> >> > without introducing accounts. Otherwise, the implication that will
> > be
> >> > drawn (and has been by several people in discussing this issue) is
> >> > that there is some implied notion of "atomic process executions".
> >> >
> >> > Thanks,
> >> > Simon
> >> >
> >> > On 3 August 2011 22:56, Luc Moreau<L.Moreau@ecs.soton.ac.uk>  wrote:
> >> >
> >> >> Hi Simon,
> >> >>
> >> >> It's good to see that we understand each other's definition of
> > derivation.
> >> >>
> >> >> Given what you say about your notion of derivation, isn't it
> > similar
> >> >> to isDerivedFromInMultipleSteps?
> >> >>
> >> >> I wonder whether we should find a better terminology for these
> > relations.
> >> >>
> >> >> Luc
> >> >>
> >> >> On 03/08/11 16:59, Simon Miles wrote:
> >> >>
> >> >>> Hi Luc,
> >> >>>
> >> >>> Sorry, just catching up with these mails. Your explanation helps
> >> >>> a lot. In particular, I think the critical point which clarifies
> >> >>> my confusion is the following:
> >> >>>
> >> >>>
> >> >>>
> >> >>>> Asserting that
> >> >>>>    isDerivedFrom(report2, data2) would be very different. It
> >> >>>> would mean that the process execution that generated report2
> >> >>>> also used data2.
> >> >>>>
> >> >>>>
> >> >>> I have always understood isDerivedFrom (A, B) as saying that "A
> > was
> >> >>> derived from B, regardless of any other assertion I make", which
> >> >>> could be expressed as "there is a conceivably assertable process
> >> >>> execution which used B and generated A".
> >> >>>
> >> >>> You are instead saying isDerivedFrom (A, B) means "A was derived
> >> >>> from B, and if I assert A as being generated by a process
> > execution,
> >> >>> that was the execution which used B and led to A being derived
> > from it".
> >> >>>
> >> >>> I agree these are semantically different. You are taking
> >> >>> "use+generate" as fundamental, where "derived" implies a process
> >> >>> which uses B and generates A takes place, so consistency within
> >> >>> an account requires that the process which generates A is the
> >> >>> same
> > that
> >> >>> is implied by derivation.
> >> >>>
> >> >>> I interpreted "derived" as fundamental itself and an independent
> >> >>> assertion, so consistency in an account is given by this
> >> >>> independence, i.e. by saying "derived" you are not implying a
> >> >>> process in the same account anyway. And the independence of the
> >> >>> assertion means that it does not even make sense to consider it
> >> >>> in conjunction with the "generates" assertion (if it exists).
> >> >>>
> >> >>> thanks,
> >> >>> Simon
> >> >>>
> >> >>> On 1 August 2011 23:59, Luc Moreau<L.Moreau@ecs.soton.ac.uk>
> > wrote:
> >> >>>
> >> >>>
> >> >>>> Hi Simon,
> >> >>>>
> >> >>>> That's a good example, thanks!
> >> >>>>
> >> >>>> Let me try and explain, how I see it:
> >> >>>>
> >> >>>> With
> >> >>>>
> >> >>>> isDerivedFrom (report1, data1)
> >> >>>>
> >> >>>> the asserter has a deep knowledge of the process execution that
> >> >>>> underpins this derivation. In particular, it is PE workflow1
> >> >>>> that generates report1, and uses data1. Hence, both the
> >> >>>> generation
> > event
> >> >>>> for report1 and the use event for data1 occur during workflow1.
> >> >>>>
> >> >>>> In the provenance challenge, when you were using slicing
> > techniques
> >> >>>> to extract derivations from process definitions, I would argue
> > you
> >> >>>> were generating similar derivations.
> >> >>>>
> >> >>>> With
> >> >>>>
> >> >>>> isDerivedFromInMultipleSteps (report2, data2)
> >> >>>>
> >> >>>> the asserter is much less precise, and does not state whether a
> >> >>>> single process is involved for generation/use, and which
> >> >>>> interval they occur in.
> >> >>>>
> >> >>>> Furthermore, in this example, with the provenance given,  one
> >> >>>> cannot ascertain whether 'unpublished2' is in the derivation
> >> >>>> path between report2 and data2.
> >> >>>>
> >> >>>> A stronger provenance would have been
> >> >>>>
> >> >>>> isDerivedFrom (report2, unpublished2)
> >> >>>>
> >> >>>> isDerivedFrom(unpublished2, data2)
> >> >>>>
> >> >>>>
> >> >>>> from which we can infer by transitive closure
> >> >>>>
> >> >>>> isDerivedFrom+ (report2, data2)
> >> >>>>
> >> >>>>
> >> >>>> So, to me,
> >> >>>> 1. isDerivedFrom is fundamental in the model, and requires
> > deep/precise
> >> >>>>       knowledge of process executions.
> >> >>>> 2. isDerivedFrom+ is useful inference (transitive closure).
> >> >>>> 3. isDerivedFromInMultipleSteps is convenience assertion, but
> >> >>>> not
> >> >>>>        as precise as 1&2.
> >> >>>>
> >> >>>> We could drop 3, but then, you wouldn't be able to express your
> >> >>>> second example.
> >> >>>>
> >> >>>> Asserting that
> >> >>>>    isDerivedFrom(report2, data2) would be very different. It
> >> >>>> would mean that the process execution that generated
> >> >>>> report2 also used data2.
> >> >>>>
> >> >>>> So,
> >> >>>>
> >> >>>> used (workflow1.2, data2, r) for some role r.
> >> >>>>
> >> >>>> But that's not the intent.
> >> >>>>
> >> >>>> What do you think?
> >> >>>> Regards,
> >> >>>> Luc
> >> >>>>
> >> >>>>
> >> >>>>
> >> >>>>
> >> >>>> On 01/08/11 16:53, Simon Miles wrote:
> >> >>>>
> >> >>>>
> >> >>>>> Hi Luc,
> >> >>>>>
> >> >>>>> OK. Here's my stab at an motivating example.
> >> >>>>>
> >> >>>>> An organisation, Org, wants to use the WG standard to record
> >> >>>>> and provide access to provenance data on the documents it makes
> >> >>>>> available online to its clients. It has storage limits on the
> >> >>>>> provenance it can maintain.
> >> >>>>>
> >> >>>>> Alice regularly receives government data sets and for each,
> >> >>>>> creates a report which is published online. Looking for a
> > minimal
> >> >>>>> way to express this using PIL, Org decides on one BOB for each
> >> >>>>> data set, one for each report, one process representing the
> >> >>>>> create-and-publish workflow, and a derivation link to show that
> >> >>>>> the report is based on the data set. A given instance of this,
> > for one data
> >> set, is:
> >> >>>>>
> >> >>>>>      bob (data1, [ type: "File", location: "/shared/crime1.data"
> > ])
> >> >>>>>      bob (report1, [ type: "File", location:
> >> >>>>> "http://example.com/report1.pdf", creator: "Alice" ])
> >> >>>>>      processExecution (workflow1, create-and-publish, t)
> >> >>>>>      isGeneratedBy (report1, workflow1, out)
> >> >>>>>      used (workflow1, data1, in)
> >> >>>>>      isDerivedFrom (report1, data1)
> >> >>>>>
> >> >>>>> A client, Clive, finds a mistake in report1, looks at the
> >> >>>>> provenance and, being "creator", Alice gets the blame. However,
> >> >>>>> the error is actually due to Bob, who published Alice's report,
> >> >>>>> messing up the axes on a graph. To avoid Alice's anger, Org
> > agrees
> >> >>>>> to refine what is modelled to a finer granularity: create, then
> >> >>>>> publish. As they have storage constraints, they will make
> >> >>>>> available only one granularity of provenance information, and
> > use
> >> >>>>> this finer granularity only for subsequent reports. A given
> > instance would
> >> be:
> >> >>>>>
> >> >>>>>      bob (data2, [ type: "File", location: "/shared/crime2.data"
> > ])
> >> >>>>>      bob (unpublished2, [ type: "File", location:
> >> >>>>> "/shared/report2.pdf",
> >> >>>>> creator: "Alice" ])
> >> >>>>>      bob (report2, [ type: "File", location:
> >> >>>>> "http://example.com/report2.pdf", creator: "Alice", publisher:
> > "Bob"
> >> >>>>> ])
> >> >>>>>      processExecution (workflow1.1, create, t)
> >> >>>>>      processExecution (workflow1.2, publish, t+4)
> >> >>>>>      isGeneratedBy (unpublished2, workflow1.1, out)
> >> >>>>>      isGeneratedBy (report2, workflow1.2, out)
> >> >>>>>      used (workflow1.1, data2, in)
> >> >>>>>      used (workflow1.2, unpublished2, in)
> >> >>>>>      isDerivedFromInMultipleSteps (report2, data2)
> >> >>>>>
> >> >>>>> Clive queries to find out what data sets the reports available
> > are
> >> >>>>> derived from. He finds that while report1 is derived from data1
> > in
> >> >>>>> one step (isDerivedFrom), report2 is derived from data2 in
> >> >>>>> multiple steps (isDerivedFromInMultipleSteps). He (like me)
> >> >>>>> does not understand how he should interpret the distinction
> >> >>>>> between
> > the
> >> >>>>> two. There is apparently something different in the way that
> >> >>>>> report2 is related to
> >> >>>>> data2 compared to how report1 is derived from data1, and
> > possibly
> >> >>>>> he should trust report2 less because of this indirect link to
> > its
> >> >>>>> source data. But Org is adamant that nothing has changed in
> > their
> >> >>>>> procedures, and there is no distinction.
> >> >>>>>
> >> >>>>> Thanks,
> >> >>>>> Simon
> >> >>>>>
> >> >>>>> On 1 August 2011 12:15, Luc Moreau<L.Moreau@ecs.soton.ac.uk>
> >> wrote:
> >> >>>>>
> >> >>>>>
> >> >>>>>
> >> >>>>>> Hi Simon,
> >> >>>>>>
> >> >>>>>> Sorry, but I don't understand.  Your initial example was not
> >> >>>>>> valid because you had two PEs generating a single BOB.
> >> >>>>>>
> >> >>>>>> If they are different ways of describing something happening
> >> >>>>>> in the world, I assume that you will identify different
> > activities,
> >> >>>>>> and hence multiple process executions will be asserted.
> >> >>>>>>
> >> >>>>>> Can you reformulate an example that illustrate your concern?
> >> >>>>>>
> >> >>>>>> Luc
> >> >>>>>>
> >> >>>>>> On 08/01/2011 12:02 PM, Simon Miles wrote:
> >> >>>>>>
> >> >>>>>>
> >> >>>>>>
> >> >>>>>>> Hi Luc,
> >> >>>>>>>
> >> >>>>>>> I follow your argument, but it seems tangential to my point.
> > The
> >> >>>>>>> following argument still seems inevitably true to me:
> >> >>>>>>>
> >> >>>>>>> Activity in the world that uses one BOB and generates another
> >> >>>>>>> *can* be described in PIL as multiple process executions or a
> >> >>>>>>> single process execution (regardless of whether it actually
> >> >>>>>>> is described in these different ways or not, or whether
> >> >>>>>>> accounts
> > are
> >> required or not).
> >> >>>>>>>
> >> >>>>>>> Therefore, what one process execution denotes is not distinct
> >> >>>>>>> from what multiple process executions denotes, we have just
> >> >>>>>>> provided more detail in the latter description (and this
> > detail
> >> >>>>>>> is, in any case, removed when saying "is derived from").
> >> >>>>>>>
> >> >>>>>>> Therefore, isDerivedFrom and isDerivedFromInMultipleSteps as
> >> >>>>>>> defined do not describe anything different in the world, so
> >> >>>>>>> we have two terms for representing the same thing.
> >> >>>>>>>
> >> >>>>>>> I know that we've debated this or similar before, but it is
> >> >>>>>>> still not clear to me where the fault lies in my argument, or
> >> >>>>>>> what isDerivedFromInMultipleSteps really represents. If it's
> >> >>>>>>> only me that's confused, I understand there are more urgent
> >> >>>>>>> concerns (though I'd still like to understand).
> >> >>>>>>>
> >> >>>>>>> Thanks,
> >> >>>>>>> Simon
> >> >>>>>>>
> >> >>>>>>> On 1 August 2011 09:25, Luc Moreau<L.Moreau@ecs.soton.ac.uk>
> >> wrote:
> >> >>>>>>>
> >> >>>>>>>
> >> >>>>>>>
> >> >>>>>>>
> >> >>>>>>>> Hi Simon,
> >> >>>>>>>>
> >> >>>>>>>> If I understand you correctly, you are suggesting that the
> >> >>>>>>>> following two assertions hold together.
> >> >>>>>>>>
> >> >>>>>>>> isGeneratedBy(e5,pe5,out)
> >> >>>>>>>> isGeneratedBy(e5,pe4,out)
> >> >>>>>>>>
> >> >>>>>>>> But this is not legal, since it is stated that one BOB is
> >> >>>>>>>> generated by at most one process execution.
> >> >>>>>>>>
> >> >>>>>>>> What you are suggesting should be encoded in a separate
> > account
> >> >>>>>>>> (though we have not defined this yet!).
> >> >>>>>>>> A one-step derivation then expands to one process execution
> > in
> >> >>>>>>>> a given account.
> >> >>>>>>>> In a separate account, there may be a multi-step derivation
> >> >>>>>>>> between the same two BOBs and it would expand into multiple
> >> >>>>>>>> process executions.
> >> >>>>>>>>
> >> >>>>>>>> Does it make sense?
> >> >>>>>>>> Regards,
> >> >>>>>>>>
> >> >>>>>>>> Luc
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>> On 07/29/2011 05:52 PM, Provenance Working Group Issue
> > Tracker
> >> wrote:
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>> PROV-ISSUE-67 (single-execution): Why is there a difference
> > in
> >> >>>>>>>>> what is represented by one vs multiple executions?
> > [Conceptual
> >> >>>>>>>>> Model]
> >> >>>>>>>>>
> >> >>>>>>>>> http://www.w3.org/2011/prov/track/issues/67
> >> >>>>>>>>>
> >> >>>>>>>>> Raised by: Simon Miles
> >> >>>>>>>>> On product: Conceptual Model
> >> >>>>>>>>>
> >> >>>>>>>>> By the definition, "a process execution represents an
> > identifiable
> >> activity". This does not seem to preclude one process execution
> > assertion
> >> denoting, at a coarse granularity, the same events in the world
> > denoted by
> >> multiple process executions in other assertions.
> >> >>>>>>>>>
> >> >>>>>>>>> If so, then in the File Scenario example, I could add a
> > coarse-
> >> grained process execution representing the whole e1-to-e5 activity:
> >> >>>>>>>>>        processExecution(pe5,collaboratively-edit,t)
> >> >>>>>>>>>        uses(pe5,e1,in)
> >> >>>>>>>>>        isGeneratedBy(e5,pe5,out)
> >> >>>>>>>>>
> >> >>>>>>>>> But then Section 5.5.2 distinguishes between "a single
> > process
> >> execution" and "one or more process executions". Following the
> > argument
> >> above, these could represent exactly the same occurrences in the
> > world.
> >> >>>>>>>>>
> >> >>>>>>>>> So there is no difference between what is denoted by one
> >> >>>>>>>>> and
> >> multiple process executions, and so no difference between
> > isDerivedFrom and
> >> isDerivedFromInMultipleSteps as described. Whether e5 was derived
> >> from
> > e1
> >> appears to me to be entirely independent of how many process
> > executions
> >> were involved.
> >> >>>>>>>>>
> >> >>>>>>>>>
> >> >>>>>>>>>
> >> >>>>>>>>>
> >> >>>>>>>>>
> >> >>>>>>>>>
> >> >>>>>>>>>
> >> >>>>>>>>>
> >> >>>>>>>>>
> >> >>>>>>>> --
> >> >>>>>>>> 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
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>
> >>
> _______________________________________________________________
> >> >>>>>>>> _______ This email has been scanned by the MessageLabs Email
> >> >>>>>>>> Security System.
> >> >>>>>>>> For more information please visit
> >> >>>>>>>> http://www.messagelabs.com/email
> >> >>>>>>>>
> >>
> _______________________________________________________________
> >> >>>>>>>> _______
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>>
> >> >>>>>>>
> >> >>>>>>>
> >> >>>>>>>
> >> >>>>>> --
> >> >>>>>> 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
> >> >>>>>>
> >> >>>>>>
> >> >>>>>>
> >> >>>>>>
> >>
> ________________________________________________________________
> >> _
> >> >>>>>> _____ This email has been scanned by the MessageLabs Email
> >> >>>>>> Security System.
> >> >>>>>> For more information please visit
> >> >>>>>> http://www.messagelabs.com/email
> >> >>>>>>
> >>
> ________________________________________________________________
> >> _
> >> >>>>>> _____
> >> >>>>>>
> >> >>>>>>
> >> >>>>>>
> >> >>>>>>
> >> >>>>>
> >> >>>>>
> >> >>>>>
> >> >>>>
> >>
> ________________________________________________________________
> >> ___
> >> >>>> ___ This email has been scanned by the MessageLabs Email
> >> >>>> Security System.
> >> >>>> For more information please visit
> > http://www.messagelabs.com/email
> >> >>>>
> >>
> ________________________________________________________________
> >> ___
> >> >>>> ___
> >> >>>>
> >> >>>>
> >> >>>>
> >> >>>
> >> >>>
> >> >>>
> >> >>
> >> >>
> >>
> ________________________________________________________________
> >> _____
> >> >> _ This email has been scanned by the MessageLabs Email Security
> >> >> System.
> >> >> For more information please visit http://www.messagelabs.com/email
> >> >>
> >>
> ________________________________________________________________
> >> _____
> >> >> _
> >> >>
> >> >>
> >> >
> >> >
> >> >
> >
> >
> >
> >
> ________________________________________________________________
> ______
> > 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 Friday, 5 August 2011 15:45:56 UTC