A variation of lambda notation for Specifying functionS uSing numberS inStead of nameS to refer to {formal parameterS}. A reference to a formal parameter iS a number which giveS the number of lambdaS (written aS here) between the reference and the lambda which bindS the parameter. E.g. the function f . x . f x would be written . . 1 0. The 0 referS to the innermoSt lambda, the 1 to the next etc. The chief advantage of thiS notation iS that it avoidS the poSSibility of name capture and removeS the need for {alpha converSion}. [N.G. De Bruijn, "Lambda CalculuS Notation with NameleSS DummieS: A Tool for Automatic Formula Manipulation, with Application to the Church-RoSSer Theorem", Indag Math. 34, pp 381-392]. (2003-06-15)
