 Definition 2.14 (Stability). Let \(D_1,\ldots,D_n, D\) be flat cpo’s and \(f: D_1\times \ldots \times D_n \to D\) monotonic (hence continuous). Then \(f\) is stable if for every \(\vec{x} = {\langle x_1,\ldots,x_n \rangle} \in D_1\times \ldots \times D_n\) there is a unique minimal element \(m(f,x) \sqsubseteq \vec{x}\) such that \(f(m(f,\vec{x})) = f(\vec{x})\).