Re: PROV-ISSUE-29 (mutual-iVP-of): can two bobs be mutually "IVP of" each other [Conceptual Model]

On Sun, Apr 1, 2012 at 21:52, Paul Groth <> wrote:
> Your example is correct...but I the common thing were talking about is the
> thing in the chair,
> But maybe the gurus should step in

I'm not claiming to be a guru on the matter, but we've had this
discussion ( a few times!) before.

If we assume every entity only maps to one thing in the world - and
all those things are distinguishable, then we are enforcing a
particular classification of things. (that there is some "real thing"
in the end). How do we define a thing? What do you mean by "the car",
do you include the petrol or not? Well, one way is to describe it as
an entity.

Two entities could be describing the ''same thing" if the two
interpretations overlap. The now famous "Customer in chair at 6pm"
entity overlaps with the  "Woman in red dress" entity - they are
alternates of the "same thing", as they are both specializations of
the same woman, let's call her Julie. CustomerInChairAt6Pm is also a
specialization of CustomerInChair, and alternate of

However they don't continue to be 'the same thing' as Julie gets up at
7pm to leave the cafe, and Bob sits down in her chair.
CustomerInChairAt6pm disappears (is *consumed* by the Leaving
activity, if you like), but Julie still wears her red dress;
JulieInRedDress lives on. The CustomerInChairAt7pm has nothing to do
with JulieInRedDress; they are not the same thing.

In this case it was the passing of time that caused the
same-thing-entities to transition to other entities which are not the
same thing.

For conceptual things this can happen in other ways, for instance,
imagine the genome sequence GATTACA is a specialization of "the human
genome sequence", which is an specialization of the actual genome
sequences from a selection of humans. However as the human genome is a
kind of idealized average, some of those humans might not have GATTACA
in their genome, and so here it would not be transitive. (I know this
is pushing it a bit, as you could rather say that the idealized
sequence is derived from the actual sequences - however you often find
derivation and specialization go hand in hand).

My signature in the end of this email is a specialization of this
email message, which is a specialization of my thoughts on this email
thread. However the signature is not a specialization of those

Stian Soiland-Reyes, myGrid team
School of Computer Science
The University of Manchester

Received on Sunday, 1 April 2012 23:12:19 UTC