Comments on the Clique Number of Zero‐Divisor Graphs of Zn

In 2008, J. Skowronek‐kaziw extended the study of the clique number ω ( G ( Z n )) to the zero‐divisor graph of the ring Z n , but their result was imperfect. In this paper, we reconsider ω ( G ( Z n )) of the ring Z n and give some counterexamples. We propose a constructive method for calculating ω ( G ( Z n )) and give an algorithm for calculating the clique number of zero‐divisor graph. Furthermore, we consider the case of the ternary zero‐divisor and give the generation algorithm of the ternary zero‐divisor graphs.