De Bruijn Notation

* 1&lt language&gt 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 Eg 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