 There is a convenient representation of continuous functionals that has been used extensively in the literature, though not by Brouwer himself. Continuous functionals that assign numbers to infinite sequences can be represented by neighborhood functions, where a neighborhood function \(f\) is a function on the natural numbers satisfying the following two properties (\(\cdot\) denotes concatenation and \(f(\alpha(\overline{n}))\) denotes the value of \(f\) on the code of the finite sequence \(\alpha(\overline{n})\)).