Informally, periodic events are events that repeat regularly in time (e.g., each Tuesday), and temporal periodicity is their temporal periodic pattern of repetition. A pattern is periodic if it can be represented by specifying a finite portion of it, and the duration of each repetition. For instance, supposing that day 1 is a Monday, the pair <‘day 2’, ‘7 days’> may implicitly represent all Tuesdays.
A useful generalization of periodic patterns is eventually periodic ones, i.e., patterns that can be expressed by the union of a periodic pattern and a finite nonperiodic one.
The above notion of periodic events can be further extended. For instance, Tuzhilin and Clifford  distinguish between strongly periodic events that occur at equally distant moments in time (e.g., a class, scheduled to meet once a week, on Wednesday at 11 a.m.); nearly periodicevents, occurring at regular periods, but not necessarily at equally distant moments of time...
- 2.Baudinet M, Chomicki J, Wolper P. Temporal deductive databases. In: Tansel A, Clifford J, Gadia S, Jajodia S, Segev A, Snodgrass R, editors. Temporal databases. Redwood City: Benjamin/Cummings; 1993. p. 294–320.Google Scholar
- 4.Chomicki J, Imielinsky T. Temporal deductive databases and infinite objects. In: Proceedings of the 7th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems; 1988. p. 61–73.Google Scholar
- 6.Kabanza F, Stevenne J-M, Wolper P. Handling infinite temporal data. In: Proceedings of the 9th ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems; 1990. p. 392–403.Google Scholar
- 7.Kurt A, Ozsoyoglu M. Modelling and querying periodic temporal databases. In: Proceedings of the 6th International Conferene and Workshop on Database and Expert Systems Applications; 1995. p. 124–133.Google Scholar
- 8.Leban B, McDonald DD, Forster DR. A representation for collections of temporal intervals. In: Proceedings of the 5th National Conference on Artificial Intelligence; 1986. p. 367–371.Google Scholar
- 9.Niezette M, Stevenne J-M. An efficient symbolic representation of periodic time. In: Proceedings of the International Conference on Information and Knowledge Management; 1992.Google Scholar
- 13.Sujatha B, Pandian SC. A survey on periodicity detection in time series database. J Glob Res Comput Sci. 2013;4(5):30–2.Google Scholar