	The stage L = Def (L) uses formulas with parameters from L to define the sets x and y. If one discounts (for the moment) the parameters, the formulas can be given a standard Gödel numbering by the natural numbers. If Φ is the formula with the smallest Gödel number that can be used to define x, and Ψ is the formula with the smallest Gödel number that can be used to define y, and Ψ is different from Φ, then let x<y if and only if Φ<Ψ in the Gödel numbering. Henceforth, we suppose that Ψ=Φ.