Dominating sets in k-majority tournaments

A k-majority tournament T on a finite vertex set V is defined by a set of 2k-1 linear orderings of V, with u→v if and only if u lies above v in at least k of the orders. Motivated in part by the phenomenon of “non-transitive dice”, we let F(k) be the maximum over all k-majority tournaments T of the size of a minimum dominating set of T.We show that F(k) exists for all k>0, that F(2)=3 and that in general C1k/logk≤F(k)≤C2klogk for suitable positive constants C1 and C2.