# Beta reduction

### From HaskellWiki

A *beta reduction* (also written *β reduction*) is the process of calculating a result from the application of a function to an expression.

For example, suppose we apply the function

(\x -> 2*x*x + y)

7

7

x

(\x -> 2*x*x + y)(7)

is *reduced* to the result

2*7*7 + y

This is a *beta reduction*.

2*7*7

98

(*)

Also see Lambda calculus and the wikipedia lambda calculus article.