## FUNCTION (The four basic types of constancy in a)
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W.R. ASHBY distinguishes four basic types of functions from the viewpoint of the extent to which a variable displays constancy, namely:

"A. The full-function has no finite interval of constancy; many common physical variables are of this type: the height of the barometer, for instance;

"B. The part-function has finite intervals of change and finite intervals of constancy;

"C. The step-function has finite intervals of constancy separated by instantaneous jumps

"D. The null-function which shows no change over the whole period of observation.

"The four types obviously include all the possibilities, except for mixed forms" (1960, p.87).

### Categories

- 1) General information
- 2) Methodology or model
- 3) Epistemology, ontology and semantics
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### Publisher

Bertalanffy Center for the Study of Systems Science(2020).

To cite this page, please use the following information:

* Bertalanffy Center for the Study of Systems Science (2020).* Title of the entry. In Charles François (Ed.), International Encyclopedia of Systems and Cybernetics (2). Retrieved from www.systemspedia.org/[full/url]

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