The Lambda Calculus

The Lambda calculus, or γ-calculus, is a model of computation based on the idea that algorithms can be seen as mathematical functions mapping inputs to outputs. It was introduced by Alonzo Church in the 1930s as a precise notation for a theory of anonymous functions; its name is due to the use of the Greek letter γ in functional expressions. Church remarked that when denoting a function by an expression such as x + y, it was not always clear what the intended function was.