Dealing with qualitative and quantitative temporal information concerning periodic events

The paper describes a framework for representing and reasoning with periodic events. It proposes a temporal formalism, which deals with both (i) quantitative information concerning the frame of time (e.g., from 1990 until 1993) and the calendar-dates (e.g., on Mondays) in which periodic events take place and (ii) the qualitative relations between periodic events (e.g., Mary works after John). The paper defines the basic operations of inversion, intersection and composition of temporal specifications expressed in the given formalism.