Solving the clique cover problem on (bull, $C_4$)-free graphs

Kathie Cameron, Chính T. Hoàng

We give an $O(n^4)$ algorithm to find a minimum clique cover of a (bull, $C_4$)-free graph, or equivalently, a minimum colouring of a (bull, $2K_2$)-free graph, where $n$ is the nu…