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| 双圈覆盖猜想指出,对于每个无桥图,都存在一组简单环可以将图的每个边缘恰好覆盖两次。然而目前其是否成立(或找到反例)仍然是一个悬而未决的问题。 | | 双圈覆盖猜想指出,对于每个无桥图,都存在一组简单环可以将图的每个边缘恰好覆盖两次。然而目前其是否成立(或找到反例)仍然是一个悬而未决的问题。 |
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− | == Graph classes defined by cycles == | + | == Graph classes defined by cycles 根据环定义的图类 == |
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| Several important classes of graphs can be defined by or characterized by their cycles. These include: | | Several important classes of graphs can be defined by or characterized by their cycles. These include: |
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| Several important classes of graphs can be defined by or characterized by their cycles. These include: | | Several important classes of graphs can be defined by or characterized by their cycles. These include: |
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− | 一些重要的图类可以由它们的圈或拥有属性来定义。其中包括:
| + | 图的几个重要类别可以由其环定义或表征。其中包括: |
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| * [[Bipartite graph]], a graph without odd cycles (cycles with an odd number of vertices). | | * [[Bipartite graph]], a graph without odd cycles (cycles with an odd number of vertices). |
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| * [[Triangle-free graph]], a graph without three-vertex cycles | | * [[Triangle-free graph]], a graph without three-vertex cycles |
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− | | + | * 二分图Bipartite graph,其中无奇数环(具有奇数个顶点的环)。 |
| + | * 仙人掌图Cactus graph,其中每个非平凡的双向连通分量都是一个环。 |
| + | * 环图Cycle graph,由一个环组成的图。 |
| + | * 弦图Chordal graph,其中每个导出环都是三角形。 |
| + | * 有向无环图Directed acyclic graph,无环的有向图。 |
| + | * 线完美图Line perfect graph,其中每个奇环都是三角形。 |
| + | * 完美图Perfect graph,无导出环或大于3的奇数路径长度的环。 |
| + | * 伪森林Pseudoforest,其中每个连通分量最多只有一个环。 |
| + | * 绞窄图Strangulated graph,其中每个边环都是三角形。 |
| + | * 强连通图Strongly connected graph,一种有向图,其中每个边都是环的一部分。 |
| + | * 无三角形图Triangle-free graph,无三个顶点环的图 |
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| == See also == | | == See also == |