“…Then, the core of Γ(R) is the maximal clique in Γ(R), [16]. On the other hand, χ(Γ(Z n [i])), and ω(Γ(Z n [i])), when n is a power of a prime are computed in, [3] and [18] respectively. Furthermore, the maximal clique, when n is a power of a prime, is determined in [18] comparing the results in the two papers, we see that, χ(Γ(Z n [i])), and ω(Γ(Z n [i])) are equal, and so we get,…”