A beta reduction (also written β reduction) is the process of calculating a result from the application of a function to an expression.
|Haskell theoretical foundations|
For example, suppose we apply the function
(\x -> 2*x*x + y)
to the value
7. To calculate the result, we substitute
7 for every free occurrence of
x, and so the application of the function
(\x -> 2*x*x + y)(7)
is reduced to the result
2*7*7 + y
This is a beta reduction.
(Further reductions could be applied to reduce
98. Although the lambdas are not explicit, they exist hidden in the definition of