论文标题

几乎所有排列矩阵都有界限饱和函数

Almost all permutation matrices have bounded saturation functions

论文作者

Geneson, Jesse

论文摘要

数十年来,禁止图的饱和问题一直是一个流行的研究领域,最近Brualdi和CAO启动了0-1矩阵饱和问题的研究。我们说,如果$ a $避免$ p $,则0-1矩阵$ a $对于禁止的0-1矩阵$ p $饱和,但是将任何零更改为$ a $中的一个零,会创建$ p $的副本。定义$ sat(n,p)$,是$ n \ times n $ 0-1矩阵中最小数量的数量,该矩阵以$ p $饱和。 Fulek和Keszegh证明,对于每0-1矩阵$ p $,$ sat(n,p)= o(1)$或$ sat(n,p)=θ(n)$。他们发现了两个0-1矩阵$ p $,其中$ sat(n,p)= o(1)$,以及无限的0-1矩阵$ p $,$ sat(n,p)=θ(n)$。他们的结果表明,几乎所有$ k \ times k $ 0-1矩阵$ p $ $ sat(n,p)=θ(n)$。 Fulek和Keszegh猜想,还有更多0-1矩阵$ p $,使得$ sat(n,p)= o(1)$除了他们发现的$(1)$,他们要求对所有置换矩阵$ p $进行表征,使得$ sat(n,p)= o(1)$。我们通过证明几乎所有$ k \ times k $ prabion矩阵$ p $都有$ sat(n,p)= o(1)$来确认他们的猜想。我们还在表征问题上取得了进展,因为我们的主要结果证明表现出具有有界饱和函数的排列矩阵家族。

Saturation problems for forbidden graphs have been a popular area of research for many decades, and recently Brualdi and Cao initiated the study of a saturation problem for 0-1 matrices. We say that 0-1 matrix $A$ is saturating for the forbidden 0-1 matrix $P$ if $A$ avoids $P$ but changing any zero to a one in $A$ creates a copy of $P$. Define $sat(n, P)$ to be the minimum possible number of ones in an $n \times n$ 0-1 matrix that is saturating for $P$. Fulek and Keszegh proved that for every 0-1 matrix $P$, either $sat(n, P) = O(1)$ or $sat(n, P) = Θ(n)$. They found two 0-1 matrices $P$ for which $sat(n, P) = O(1)$, as well as infinite families of 0-1 matrices $P$ for which $sat(n, P) = Θ(n)$. Their results imply that $sat(n, P) = Θ(n)$ for almost all $k \times k$ 0-1 matrices $P$. Fulek and Keszegh conjectured that there are many more 0-1 matrices $P$ such that $sat(n, P) = O(1)$ besides the ones they found, and they asked for a characterization of all permutation matrices $P$ such that $sat(n, P) = O(1)$. We affirm their conjecture by proving that almost all $k \times k$ permutation matrices $P$ have $sat(n, P) = O(1)$. We also make progress on the characterization problem, since our proof of the main result exhibits a family of permutation matrices with bounded saturation functions.

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