Bitemporal Data

Chapter 7

The Allen Relationships

This chapter describes the Allen relationships, which are a list of all possible positional relationships between two time periods located on a common timeline. It groups the Allen relationships under the nodes of a taxonomy, thereby demonstrating that they are a partitioning.

Keywords

Allen relationships; clock tick; closed/open; time period

Any given time period may be longer or shorter than another time period, or the same duration as that other time period. It may begin or end before or after that other time period, or at the same time that that other time period begins or ends. Two adjacent time periods – time periods with no other time periods between them – may or may not have a temporal gap between them, ...