The $n$-Queens Problem in Higher Dimensions

TL;DR

This paper explores the n-queens problem extended to higher-dimensional chess spaces, establishing new bounds on the minimum number of queens needed to attack all positions in such spaces.

Contribution

It introduces the first lower bounds on the number of queens required to cover all positions in higher-dimensional chess spaces.

Findings

n queens do not always suffice to attack all positions in higher dimensions

Established the first lower bounds on the number of queens needed in d-dimensional spaces

Showed that for any k, some higher-dimensional spaces cannot be fully attacked by n^k queens

Abstract

A well-known chessboard problem is that of placing eight queens on the chessboard so that no two queens are able to attack each other. (Recall that a queen can attack anything on the same row, column, or diagonal as itself.) This problem is known to have been studied by Gauss, and can be generalized to an (n \times n) board, where (n \geq 4). We consider this problem in $d$-dimensional chess spaces, where (d \geq 3), and obtain the result that in higher dimensions, $n$ queens do not always suffice (in any arrangement) to attack all board positions. Our methods allow us to obtain the first lower bound on the number of queens that are necessary to attack all positions in a $d$-dimensional chess space of size $n$, and further to show that for any $k$, there are higher-dimensional chess spaces in which not all positions can be attacked by (n^k) queens.