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Main Authors: Oh, Seunghwan, Schmitt, John R., Wang, Xianzhi
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2401.03119
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author Oh, Seunghwan
Schmitt, John R.
Wang, Xianzhi
author_facet Oh, Seunghwan
Schmitt, John R.
Wang, Xianzhi
contents In 1976 Martin Gardner posed the following problem: ``What is the smallest number of [queens] you can put on an [$n \times n$ chessboard] such that no [queen] can be added without creating three in a row, a column, or a diagonal?'' The work of Cooper, Pikhurko, Schmitt and Warrington showed that this number is at least $n$, except in the case when $n$ is congruent to $3$ modulo $4$, in which case one less may suffice. When $n>1$ is odd, Gardner conjectured the lower bound to be $n+1$. We prove this conjecture in the case that $n$ is congruent to 1 modulo 4. The proof relies heavily on a recent advancement to the Combinatorial Nullstellensatz for zero-sum grids due to Bogdan Nica.
format Preprint
id arxiv_https___arxiv_org_abs_2401_03119
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Repeatedly applying the Combinatorial Nullstellensatz for Zero-sum Grids to Martin Gardner's minimum no-3-in-a-line problem
Oh, Seunghwan
Schmitt, John R.
Wang, Xianzhi
Combinatorics
05D40
In 1976 Martin Gardner posed the following problem: ``What is the smallest number of [queens] you can put on an [$n \times n$ chessboard] such that no [queen] can be added without creating three in a row, a column, or a diagonal?'' The work of Cooper, Pikhurko, Schmitt and Warrington showed that this number is at least $n$, except in the case when $n$ is congruent to $3$ modulo $4$, in which case one less may suffice. When $n>1$ is odd, Gardner conjectured the lower bound to be $n+1$. We prove this conjecture in the case that $n$ is congruent to 1 modulo 4. The proof relies heavily on a recent advancement to the Combinatorial Nullstellensatz for zero-sum grids due to Bogdan Nica.
title Repeatedly applying the Combinatorial Nullstellensatz for Zero-sum Grids to Martin Gardner's minimum no-3-in-a-line problem
topic Combinatorics
05D40
url https://arxiv.org/abs/2401.03119