# Involution

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## involution

[‚in·və′lü·shən]*x*′ = (

*ax*+

*b*)/(

*cx*-

*a*), where

*a*

^{2}+

*bc*≠ 0.

*The Great Soviet Encyclopedia*(1979). It might be outdated or ideologically biased.

## Involution

(raising to a power), an algebraic operation consisting in repeating a quantity *a n* number of times:

The number *a* is the base of the power, *n* is the exponent, and *a ^{n}* is the power. For example, 3x3x3x3 = 3

^{4}= 81. The second power of a number is called its square and the third power, its cube.

## Involution

(regression), in biology, a reduction or loss, in the process of evolution, of certain organs, and a simplification of their organization and functions (for example, various degrees of intestinal reduction in certain parasitic worms and arthropods). Degenerative changes in protozoans and bacteria caused by unfavorable conditions in the habitat are also called involutional. In medicine, the term sometimes refers to atrophy of organs and tissues, such as in aging.