Open ajnelson-nist opened 1 year ago
Thanks for the very detailed comment.
We only used some of the possible OWL axioms, in particular we did not attempt to complete the possible owl: AsymmetricProperty
, owl:ReflexiveProperty
, owl:IrreflexiveProperty
, owl:FunctionalProperty
, owl:InverseFunctionalProperty
.
Maybe we should have.
However, the issues you raise may be dealt with in the 'extension' to OWL-Time where we attempted to complete the set of topological relations - see https://www.w3.org/TR/vocab-owl-time-rel/ in particular see https://www.w3.org/TR/vocab-owl-time-rel/#new-relations
As you will observe, this work, though several years old now, has not progressed past 'Note' status. This was partly because we needed more evidence that these additional relations were in fact needed. Your comment appears to confirm that they are.
This is an Issue about how to interpret a certain property in OWL-Time,
time:before
. There is a detour through PROV that explains why I'm asking. It is possible this issue also shows a point of needed clarification in the current OWL-Time draft.While reviewing the non-normative alignment of TIME and PROV here ...
https://github.com/w3c/sdw/blob/gh-pages/time/rdf/time-prov.ttl
... I saw that there is an alignment axiom for
prov:Activity
:From working with PROV, I had come to think it would be more appropriate for
prov:Activity
to be a subclass oftime:ProperInterval
. However, when double-checking my sources, I wasn't able to find a strict requirement that, given aprov:Activity
with aprov:Start
andprov:End
, thatprov:Start
was required to happen strictly beforeprov:End
.From review of PROV-CONSTRAINTS, I came across this evidence that a
prov:Activity
is permitted to be instantaneous:Where all this circles back to OWL-Time: I see two properties that can be used to relate one
time:Instant
to anothertime:Instant
,time:before
andtime:after
. The definitions, as currently worded, do not make explicit whether the properties permit equality of the instants being related. Personally, my normal reading of the words "before" and "after" imply a strict-inequality relationship; but, apparently W3C editorial policy in the past has permitted a standard to be posted where "precedes" could be defined as "<=", so now I feel the need to check.If I have a statement
x time:before y .
, canx
andy
refer to the sametime:Instant
?For the sake of finding a way to align with the "precedes" definition in PROV-CONSTRAINTS: Is there a predicate in OWL-Time that defines "<=" between
time:Instant
s?Should one of
time:before
ortime:after
be designated anowl: AsymmetricProperty
? Anowl:ReflexiveProperty
orowl:IrreflexiveProperty
?time:before
is currently aowl:TransitiveProperty
, so it seems some thought was put into property specializations, but I'm not sure where notes on those specializations might be.