arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2012.08821math.COmath.PR
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随机图上的分支对策

Component Games on Random Graphs

Rani Hod, Michael Krivelevich, Tobias Müller, Alon Naor, Nicholas Wormald

摘要:

在图$G$上进行的$\left(1:b\right)$组件博弈中,两个参与者,Maker和Breaker,分别交替地声明$G$的~ $1$和~ $b$先前未声明的边。制造商的目标是最大限度地提高她的图中的最大连接组件的大小,而断路器正试图最小化it. We表明,在二项式随机图的游戏的结果是强烈相关的外观的非空的$(b+2)$ -核心的图形。对于任意整数$k$,一个图的$k$ -核心是它的最小度至少为$k$的最大子图。Pittel、Spencer和Wormald在1996年指出,对于任何$k\ge3$,都存在一个明确定义的常数$c_{k}$,使得$p=c_{k}/n$是$G(n,p)$中$k$ -核心出现的阈值函数。更准确地说,当$c>c_{k}$为常数时,$G(n,c/n)$具有WHP线性大小的$k$ -核心,当$c<c_{k}$为常数时,具有WHP空的$k$ -核心。我们发现,对于任何正常数$b$,当玩$(1:b)$组件游戏$G(n,c/n)$,制造商可以WHP建立一个线性大小的组件,如果$c>c_{b+2}$,而断路器可以WHP防止制造商从建设大于多面体大小的组件,如果$c<c_{b+2}$。对于Breaker的策略,我们证明了一个定理,这可能是独立的利益。计算任何图的$k$核的标准算法是重复删除(“剥离”)度小于$k$的所有顶点,只要这些顶点仍然存在。当$G(n,c/n)$用于$c<c_{k}$时,Jiang,Mitzenmacher和Thaler表明,$\log_{k-1}\log n+Θ(1)$剥离迭代是WHP必要的,并且足以获得~ $G$的(空)$k$ -核心。我们的定理表明,在经过恒定次数的迭代之后,$G$已经被WHP粉碎成多对数大小的碎片。

英文摘要:

In the $\left(1:b\right)$ component game played on a graph $G$, two players, Maker and Breaker, alternately claim~$1$ and~$b$ previously unclaimed edges of $G$, respectively. Maker's aim is to maximise the size of a largest connected component in her graph, while Breaker is trying to minimise it. We show that the outcome of the game on the binomial random graph is strongly correlated with the appearance of a nonempty $(b+2)$-core in the graph. For any integer $k$, the $k$-core of a graph is its largest subgraph of minimum degree at least $k$. Pittel, Spencer and Wormald showed in 1996 that for any $k\ge3$ there exists an explicitly defined constant $c_{k}$ such that $p=c_{k}/n$ is the threshold function for the appearance of the $k$-core in $G(n,p)$. More precisely, $G(n,c/n)$ has WHP a linear-size $k$-core when the constant $c>c_{k}$, and an empty $k$-core when $c<c_{k}$. We show that for any positive constant $b$, when playing the $(1:b)$ component game on $G(n,c/n)$, Maker can WHP build a linear-size component if $c>c_{b+2}$, while Breaker can WHP prevent Maker from building larger than polylogarithmic-size components if $c<c_{b+2}$. For Breaker's strategy, we prove a theorem which may be of independent interest. The standard algorithm for computing the $k$-core of any graph is to repeatedly delete ("peel") all vertices of degree less than $k$, as long as such vertices remain. When $G(n,c/n)$ for $c<c_{k}$, it was shown by Jiang, Mitzenmacher and Thaler that $\log_{k-1}\log n+Θ(1)$ peeling iterations are WHP necessary and sufficient to obtain the (empty) $k$-core of~$G$. Our theorem states that already after a constant number of iterations, $G$ is WHP shattered into pieces of polylogarithmic size.

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