Hi Martin,
Indeed the intention is to cover parts regardless spatial or temporal
order, because
in general they cannot be distinguished. Even "mainly temporal parts",
such as a period following another, spreads out over space.
Consequently, for some time, both coexist at
different places. This is why we are now introducing true spacetime
volumes into the CRM.
They are more realistic.
If we feel this should be clearer in the scope note and examples, that
could resolve the issue?
On 13/5/2014 12:14 μμ, Martin Scholz wrote:
Hi,
the discussion so far is only concerned about part-whole in time. E3
and E4, however, both also extend in space -- but they use different
CRM classes:
an E3 Condition State is limited to an E18 Physical Thing, an E4
Period is limited to an E53 Place. E2, however, is only located in
time, not in space.
Exactly, this is why my opinion is they cannot be mixed.
Best,
Martin
The scope notes of P5 and P9 do not explicitly address the spatial
aspect. The examples are only about temporal parts.
I could think of spatial parts like
- period Renaissance has parts Italian/... Renaissance or
- the condition state of an ensemble being in ruins but with its parts
having different states of decay or even being intact.
So my question is whether P5 and P9 are intended to only cover
temporal or also spatial part-whole-relations.
Regards
Martin Scholz
Am 13.05.2014 09:58, schrieb martin:
Dear Simon,
I have the impression that you take the density of time, to which CRM
commits,
for the decomposition of phenomena happening in time, which is E2,
the nature of E2 is not the nature of time however.
Further, you seem to talk about the question if there are minimal
elements, that
cannot be subdivided further. For time, the CRM does not assume that,
as you
argue. Currently, the CRM assumes only for Actor minimal elements of
decomposition.
The first question is rather, if there are phenomena in time that
reveal a
structure with distinct recognizable identities that have a part-whole
relationship, such as "Early Minoan" and "Middle Minoan". They are
identified
by observable characteristics, not by subdivision on the time-line.
The second question is, if these part-whole relationships can be
mixed between
subcategories: Can a natural part of a Condition State be an Event,
or can a E4
Period ever have a part which is a Condition State? If not, then a
common
property would produce "non-intended models" as Nicola Guarino
describes it.
This cannot always be avoided, but we try to minimalize this effect.
Finally, CRM properties are optional, so there is no commitment given
by the
definition of a part-of property, that all instances of that class
must have
parts. Indeed, for material objects, we may end up with nuclear
particles as end
points, but those are out of scope, but long before, the notion of a
Physical
Object would loose its meaning.
If there is a characteristic class in scope which forms the minimal
elements,
then we would model the decomposition down to this class, as in the
case of
Actor and Person.
The question if the labels of these part-of relations should be
different is
interesting. So far we have prefered that they have all the same
name, because
that renders the meaning clearly, but different P-number, which
renders the
constraint. To include the class name in the label may be another
method to
render the constraint, but it produces long names difficult for
translation, and
is counterintuitive when used with subclasses, such as an Event
consisting of
several Periods, or a Period consisting of Events, which is intended.
Comments?
Martin
On 13/5/2014 12:51 ??, Simon Spero wrote:
On Mon, May 12, 2014 at 3:53 PM, Stephen Stead <[email protected]
<mailto:[email protected]>> wrote:
The question is not could we generalise the property to E2 but are
there potential instances of E2 that are not E3's or E4's that
potentially do not have decomposition. I do not know and
additionally I am not sure I want to
spend a lot of time making sure that by their very nature all E2's
are decomposable!!
This actually a rather significant ontological decision.
If there are temporal entities that cannot be so divided then the
underlying
temporal ontology is /discrete. /
If every temporal entity can always be so decomposed, then the
underlying
temporal ontology is /dense/.
CRM is committed to a dense ontology (because of the approximate
model of time
points, and the rejection of any momentary events*) , so it would
seem all E2
must be decomposable.
It is of course, not the case that the type of every part is the
same as the
type of the whole; conversely, there may be certain granularities
where each
part /is/ of the same type - e.g. the granularity of a step, each
part of a
walk is also a walk.
Simon
* e.g. "the upward velocity of the ball I just tossed becoming zero"
is not
considered to be momentary, in spite of calculus, because the precise
beginning and end points are cannot be defined as equal, just not
distinguishable.
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