Almost-full transversals in equi-$n$-squares
Abstract
In 1975, Stein made a wide generalisation of the Ryser-Brualdi-Stein conjecture on transversals in Latin squares, conjecturing that every equi--square (an array filled with symbols where each symbol appears exactly times) has a transversal of size . That is, it should have a collection of entries that share no row, column, or symbol. In 2017, Aharoni, Berger, Kotlar, and Ziv showed that equi--squares always have a transversal with size at least . In 2019, Pokrovskiy and Sudakov disproved Stein's conjecture by constructing equi--squares without a transversal of size , but asked whether Stein's conjecture is approximately true. I.e., does an equi--square always have a transversal with size ? We answer this question in the positive. More specifically, we improve both known bounds, showing that there exist equi--squares with no transversal of size and that every equi--square contains disjoint transversals of size .
Cite
@article{arxiv.2412.07733,
title = {Almost-full transversals in equi-$n$-squares},
author = {Debsoumya Chakraborti and Micha Christoph and Zach Hunter and Richard Montgomery and Teo Petrov},
journal= {arXiv preprint arXiv:2412.07733},
year = {2024}
}
Comments
16 pages, 2 figures