We adopted Allen's temporal logic, probably prematurely, thinking we could rely on
a well received theory. In the meanwhile, it turns out that Allen's logic does not work
properly both for fuzzy dates and for incomplete knowledge. There are temporal relations
which come from observation, but can only be represented by OR combinations of Allen's
relationships. That causes problems in RDF - we need superproperties of Allen's to represent
an OR. The other problem is that equality in time can only come from numerical declaration
of a date, but not from observation, except if the event is identical.