Hans Jürgen Ohlbach:
Sergei N. Artemov, Howard Barringer, Artur d'Avila Garcez, Luís C. Lamb, John Woods (editors):
Modelling Periodic Temporal Notions by Labelled Partitionings
    of the Real Numbers - The PartLib Library.
Abstract
The key notion for modelling calendar systems and many other
    periodic temporal notion is the mathematical concept of a partitioning of
    the real numbers. A partitioning of R splits the time axis into a sequence
    of intervals. Basic time units like seconds, minutes, hours, days, weeks,
    months, years etc. can all be represented by partitionings of R with nite
    partitions. Besides the basic time units in calendar systems, there are a
    lot of other temporal notions which can be modelled as partitions: the
    seasons, the ecclesiastical calendars, nancial years, semesters at
    universities, the sequence of sunrises and sunsets, the sequence of the
    tides, the sequence of school holidays etc. In this chapter a
    formalisation of periodic temporal notions by means of labelled
    partitionings of R is presented. The formalism is implemented as the C++
    library PartLib (Partitioning Library). The interface to PartLib is
    presented in the appendix. 
      
URL:
http://rewerse.net/publications/rewerse-publications.html#REWERSE-RP-2005-135
@article{REWERSE-RP-2005-135,
	author = {Hans J\"urgen Ohlbach},
	title = {Modelling Periodic Temporal Notions by Labelled Partitionings
    of the Real Numbers - The PartLib Library},
	journal = {},
	year = {2005},
	volume = {2},
	pages = {453--498},
	url = {http://rewerse.net/publications/rewerse-publications.html#REWERSE-RP-2005-135}
}