Lambda Calculus

Developed by Alonzo Church and Stephen Kleene to address the Computable Number problem. In the lambda calculus, $\lambda$ is defined as the Abstraction Operator. Three theorems of lambda calculus are $\lambda$-conversion, $\alpha$-conversion, and $\eta$-conversion.

See also Abstraction Operator, Computable Number

References

Penrose, R. The Emperor's New Mind: Concerning Computers, Minds, and the Laws of Physics. Oxford, England: Oxford University Press, pp. 66-70, 1989.