Re: [sdw] intervalDuring can really compare the values of two date time stamps


Thank you for your answer. But I am not very convinced.
I have tried an example about the ontologie, I have set four time instants:
begin1: xsd:2017-07-24;
begin2: xsd:2017-07-20;
end1: xsd:2017-07-21;

two intervals with the object properties:
interval1: hasBeginning begin1
interval1: hasEnd end1

interval2:  hasBeginning begin2
interval2:hasEnd end2

and the swrl is like following:
Interval(?inter1) ^ Interval(?inter2) ^ before(?inter2, ?inter1) ^
Person(?per) -> isParent(?per, true)

however, Bob which is the individuals of Person cannot be inferred to have
the data property "isParent: true"
So, that is to say, in fact, the comparison of those two intervals is not
executed. How do you think? (I have also sent you the ontologie of the

Mingming QIU

2018-07-19 15:49 GMT+02:00 Chris Little <>:

> Timestamps, such as defined in IETF RFC 3339 [
> rfc3339 ] which is based on ISO 8601, can be compared and 'before',
> 'after', 'same time', 'during', 'overlapping', etc can be correctly
> established.
> However, in general, two timestamps cannot be subtracted to give a
> duration, unless the calendars are precisely known and correctly
> implemented.
> Please note that some implementations that look like timestamps, such as
> Posix or Unix seconds since the 1970-01-01T00:00:00.000Z epoch are not well
> behaved, as they do not always have a strictly monotonic sequence of
> increasing times. For example, to cope with leap seconds, Posix
> implementations reset the clock to the previous second. If the clock count
> is more frequent than every second, the clock times 'jump backwards' in
> this case, rather than pause and 'mark time'.
> Does this answer your question?
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Received on Tuesday, 24 July 2018 09:32:05 UTC