In the paper [3], the theorem that at least \( \frac{n – 1}{2} \) queens are required to dominate the \( n \times n \) chessboard was attributed to P. H. Spencer, in [1]. A proof of this result appeared in the earlier work [2].
Citation
William D. Weakley. A Lower Bound For Domination Numbers Of The Queen’s Graph: Addendum[J], Journal of Combinatorial Mathematics and Combinatorial Computing, Volume 047. 231-254. DOI: .