these phases in fact define the convex hull for C. Then, E h is computed by subtracting the total energy of 𝑆 𝐶 from the energy of the most stable phase 𝑆 0 𝐶 or from the linear combination of phases 𝑆 0 𝐶 𝑖 . Here we assert that, for any 𝑆 𝐶 , the value of E h is not necessarily a fixed value.