论文标题
在六角形网格和无限树上进行消防
Firefighting on the Hexagonal Grid and on Infinite Trees
论文作者
论文摘要
$ k $消防员在无限图$ g $上的消防员问题是一个迭代的图形过程,定义如下:假设在1转1的v(g)$ in V(g)$中爆发大火。未保护的顶点。消防员的目标是最终停止大火的传播。如果有$ k $消防员最终停止火灾传播的策略,那么我们说$ g $是$ k $ - 连接。 我们考虑了六边形网格上的消防员问题,该图是其顶点和边缘正常的顶点和边缘的图形。尚不清楚六边形网格是否可连接$ 1 $。在Arxiv:1305.7076 [Math.co]中,显示消防员每回合有一名消防员,两圈额外的消防员有一名消防员,则消防员可以包含火。我们通过证明即使在一圈只有一名额外的消防员,消防员仍然可以包含火力来改进结果。 此外,我们还探索了出生序列树的$ k $接合度,它们是无限的根树,具有同一级别的每个顶点的特性都具有相同的程度。出生序列森林是一个无限的森林,其每个成分都是出生序列树。对于出生序列树和森林,大火总是从每棵树的根部开始。我们提供了一种伪多种时段算法,以决定是否可以保护所有固定水平的顶点。
The firefighter problem with $k$ firefighters on an infinite graph $G$ is an iterative graph process, defined as follows: Suppose a fire breaks out at a given vertex $v\in V(G)$ on Turn 1. On each subsequent even turn, $k$ firefighters protect $k$ vertices that are not on fire, and on each subsequent odd turn, any vertex that is on fire spreads the fire to all adjacent unprotected vertices. The firefighters' goal is to eventually stop the spread of the fire. If there exists a strategy for $k$ firefighters to eventually stop the spread of the fire, then we say $G$ is $k$-containable. We consider the firefighter problem on the hexagonal grid, which is the graph whose vertices and edges are exactly the vertices and edges of a regular hexagonal tiling of the plane. It is not known if the hexagonal grid is $1$-containable. In arXiv:1305.7076 [math.CO], it was shown that if the firefighters have one firefighter per turn and one extra firefighter on two turns, the firefighters can contain the fire. We improve on this result by showing that even with only one extra firefighter on one turn, the firefighters can still contain the fire. In addition, we explore $k$-containability for birth sequence trees, which are infinite rooted trees that have the property that every vertex at the same level has the same degree. A birth sequence forest is an infinite forest, each component of which is a birth sequence tree. For birth sequence trees and forests, the fire always starts at the root of each tree. We provide a pseudopolynomial time algorithm to decide if all the vertices at a fixed level can be protected or not.