Beta reduction

A beta reduction (also written β reduction) is where you actually apply a lambda function to an expression to generate a result.

Haskell theoretical foundations General: Mathematics - Category theory Research - Curry/Howard/Lambek Lambda calculus: Alpha conversion - Beta reduction Eta conversion - Lambda abstraction Other: Recursion - Combinatory logic Chaitin's construction - Turing machine Relational algebra

For example, suppose we have

2*x*x + y

If we now replace every occurance of x with 7, we arrive at

2*7*7 + y

We have thus performed a beta reduction.

Also see Lambda calculus and the wikipedia lambda calculus article.