The zero-divisor graph of a commutative semigroup with zero is a graph whose vertices are the nonzero zero-divisors of the semigroup, with two distinct vertices joined by an edge if their product in the semigroup is zero. In this paper, we provide formulas to calculate the numbers of non-isomorphic zero-divisor semigroups corresponding to star graphs \(K_{1,m}\), two-star graphs \(T_{m,n}\), and windmill graphs, respectively.
1970-2025 CP (Manitoba, Canada) unless otherwise stated.