 The choice between instants and intervals as the primary objects of temporal ontology has been a highly debated philosophical theme since the times of Zeno and Aristotle. Technically, the two types of temporal ontologies are closely related, and they are reducible to each other: on the one hand, time intervals can be defined by pairs of time instants (beginning and end); on the other hand, a time instant can be construed as a degenerate interval, viz. as a point-interval whose beginning and end points coincide.