  This paper concentrates on the representation of the legal relations that
obtain between parties once they have entered a contractual agreement and their
evolution as the agreement progresses through time. Contracts are regarded as
process and they are analysed in terms of the obligations that are active at
various points during their life span. An informal notation is introduced that
summarizes conveniently the states of an agreement as it evolves over time.
Such a representation enables us to determine what the status of an agreement
is, given an event or a sequence of events that concern the performance of
actions by the agents involved. This is useful both in the context of contract
drafting (where parties might wish to preview how their agreement might evolve)
and in the context of contract performance monitoring (where parties might with
to establish what their legal positions are once their agreement is in force).
The discussion is based on an example that illustrates some typical patterns of
contractual obligations.
