Dear Christian-Emil,
On 3/14/2019 11:15 AM, Christian-Emil Smith Ore wrote:
I will not continue the discussion of identifying an instance of E18
Physical Thing with its spacetimevolume.
The intention with my “explanations” was to see whether the current
model support an equality of P4 and P160 from E4 and downwards. In a
FOL description of CRM the cardinality constraints are not just
guidelines, they have strong implications on the model. For example:
1) P160 (E92 <-> E52) has the cardinality constraint (1,1:1,1)
and is a 1-1 mapping (isomorphism) between E92 and E52
2) P4 (E2 <-> E52) has the cardinality constraint (1,1:1,1) and
is a mapping between E2 and E52 where all instances of E52 is related
to one or more instances of E2.
1 & 2 say that all time-spans are a time-span both for an instance of
E92 and at least one instance of E2. There are no instance of E2,
which does not share a time-span with a STV. This, I believe, is not
the intention.
If we change the cardinality of P4 (E2 <-> E52) from (1,1:1,n) to
(1,1:1,1) which is required if P2 and P160 should be equal when
lowered to E4 <-> E52, the result is even worse. Then E2 and P52 is in
a 1-1 correspondence.
Therefore the cardinality of P4 and P160 should be (1,1: 0,1) allowing
instances of E52 to be a time-span for an instance of E2 without
being a time-span for an instance of E52 and vice versa.
Yes!
Still there is nothing in the formal FOL definition stating that P4
and P160 seen as properties between E4 and E52 are equal here Martin’s
additional FOL expression comes in:
(P4(x,y) ∧E4(x)) ⊃ P160(x,y) ∧ (P160(x,y) ∧E4(x)) ⊃ P4(x,y)
This expression states that P4 and P160 is equivalent when the domain
is restricted to P4.
Would that mean that each instance of E4 must have two time-spans, one
for the P4 and one for the P160?
Another solution could be the infamous "punning": Declare P4 to have two
domains, E2 and E92. Makes life easy, until we know the "true"
superclass of both. Isn't it? That is actually what we mean but do not
dare to say;-).
Martin
This is the only such restriction in CRM. The question is where to put
this FOL expression. One could perhaps introduce multiple inheritance
for properties and then introduce a subproperty of P4 and P160?
In any case, the 326 issue requires that the cardinalities are changed
and that the scopenote of P4 is changed to
“This property describes the temporal confinement of an instance of an
E2 Temporal Entity. The related E52 Time-Span is understood as the
real Time-Span during which the phenomena were active, which make up
the temporal entity instance. It does not convey any other meaning
than a positioning on the “time-line” of chronology. The Time-Span in
turn is approximated by a set of dates (E61 Time Primitive).
Time-Spans may have completely unknown dates but other descriptions by
which we can infer knowledge.”
Christian-Emil
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------------------------------------
Dr. Martin Doerr
Honorary Head of the
Center for Cultural Informatics
Information Systems Laboratory
Institute of Computer Science
Foundation for Research and Technology - Hellas (FORTH)
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Web-site: http://www.ics.forth.gr/isl
