Beta reduction
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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)
to the value 7
. To calculate the result, we substitute 7
for every 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 2*7*7
to 98
. Although the lambdas are not explicit, they exist hidden in the definition of (*)
.)
Also see Lambda calculus and the wikipedia lambda calculus article.