 Recursive functions have the important property that, for each given set of values of the arguments, the value of the function can be computed by a finite procedure. Similarly, recursive relations (classes) are decidable in the sense that, for each given \(n\)-tuple of natural numbers, it can be determined by a finite procedure whether the relation holds or does not hold (the number belongs to the class or not), since the representing function is computable. (Gödel 1934, 348)