What predicates / datatype properties to use with EDTF datetimes, intervals, and sets?

[rybesh]

Predicates or datatype properties that are intended to be used with any rdfs:Literal value, like dcterms:date, can obviously be used with EDTF. But what if we want to be more specific about what an EDTF value is asserting?

For example, the Time Ontology defines two datatype properties for asserting the temporal position of an instant using XSD datatypes: time:inXSDDate (with a range of xsd:date) and time:inXSDDateTimeStamp (with a range of xsd:dateTimeStamp).

Following that example, the draft EDTF Ontology defines the edtfo:inEDTFDateTime datatype property (with a domain of time:Instant) for asserting the temporal position of an instant using EDTF. (There is no sense in defining an inEDTFDate property since EDTF does not have separate datatypes for dates and datetimes.)

However, instants are not the only kinds of entities that can have their positions described using EDTF. Since it is also possible to assert the position of a temporal interval using EDTF, the draft EDTF Ontology also defines the edtfo:hasEDTFDateTimeDescription datatype property (with a domain of time:Interval) for this purpose.

Finally, “sets” of instants can have their positions described using EDTF. The Time Ontology has no notion of an “instant set.” But maybe we can model sets of instants as subclasses of time:Instant? Assuming that we can, the draft EDTF Ontology defines the edtfo:hasEDTFDateTimeSetDescription datatype property (with a domain of owl:Class).

This is a bit weird, but it opens the door to some nice things like reasoning about instant sets using disjoint unions of class expressions (so that, for example, if we learn that one class in the disjoint union is the class to which some instant belongs, we can rule out the other classes for that instant). One interesting aspect of modeling instant sets as classes is that the only difference between EDTF “one of” and “all of“ sets is that an “all of” set defines a subclass of time:Instant, while a “one of” both defines a subclass of time:Instant and asserts that some specific instant is a member of that subclass.