Event

An event is, simply, a logical predicate that maps time-points or time-intervals into truth values.

Properties of Events

Events may undergo Initiation or Termination at particular time-points or time-intervals.

Events also have certain optional properties, e.g.

Event Persistence: the property of maintaining roughly constant truth value after initiated, until terminated
Event Continuity: for non-persistent events, the property of maintaining continuous rather than discontinuous variaton in truth value over time

These are not intrinsic properties of events; events may gain or lose persistence or continuity during the course of their existence.