Azarbaijan Shahid Madani University Communications in Combinatorics and Optimization 2538-2128 10 1 2025 03 01 Cliques in the extended zero-divisor graph of finite commutative rings 195 206 14651 10.22049/cco.2023.28740.1693 EN Shariefuddin Pirzada Department of Mathematics, University of Kashmir, Srinagar, India Aaqib Altaf Department of Mathematics, Lovely Professional University, Punjab, India Journal Article 2023 06 11 Let $R$ be a finite commutative ring with or without unity and $\Gamma_{e}(R)$ be its extended zero-divisor graph with vertex set $Z^{*}(R)=Z(R)\setminus \lbrace0\rbrace$ and two distinct vertices $x,y$ are adjacent if and only if $x.y=0$ or $x+y\in Z^{*}(R)$. In this paper, we characterize finite commutative rings whose extended zero-divisor graph have clique number $1 ~ \text{or}~ 2$. We completely characterize the rings of the form $R\cong R_1\times R_2 $, where $R_1$ and $R_2$ are local, having clique number $3,~4~\text{or}~5$. Further we determine the rings of the form $R\cong R_1\times R_2 \times R_3$, where $R_1$,$R_2$ and $R_3$ are local rings, to have clique number equal to six. https://comb-opt.azaruniv.ac.ir/article_14651_59ed0dc4aa23eb078b9331b9dfc309f6.pdf