2026/07/25 by Jiangdong Ai, Xiangjie Yi
#math.CO
A k-majority tournament on a finite vertex set is defined by 2k-1 linear orders, with u→ v when u lies above v in at least k of the orders. Let F(k) be the maximum, over all k-majority tournaments, of the size of a minimum dominating set. Alon, Brightwell, Kierstead, Kostochka, and Winkler proved that C1k/log k ≤ F(k) ≤ C2klog k for suitable positive constants C1 and C2. In this paper, we prove the linear lower bound F(k)≥ \lfloor(k+1)/(2)\rfloor for k≥ 3.