If the edges are ordered pairs of vertices then we get the notions of a directed graph and directed multigraph . 如果边都是顶点的有序对，则得到有向图和有向重图的概念。
In general, the operation of insertion of removal of vertices of degree 2 does not affect the planarity of a graph . 一般地，插入或移去2次顶点运算，并不影响一个图的平面性。
If two edges of a graph are incident to the same pair of vertices, then these two edges are called parallel edges . 如果一个图的两条边关联于同一对顶点，则这两条边称为平行边。
An articulation point is a vertex of a connected graph which can be split to yield an unconnected graph . 如果一个连通图的一个顶点能被分割，从而使这图成为一个不连通图，则这个顶点称为断点。
With kuratowski's theorem, there is at least a criterion to use in discussing the nonplanarity of a graph . 有了库拉图夫斯基定理，在讨论一个图的非平面性时，至少就有了一个判别准则可供使用。
Among other things, they introduced an improved arrangement for generating holograms which is illustrated in fig 14. 36 . 他们除了别的东西以外，还引入了一种产生全息图的改进装置，如图1436所示。
This reduction also enables us to obtain some information about the number of colourings of a graph with a given set of colours . 这种化法也能使我们得到关于用给定的颜色集对一个图的着色的数目的某些信息。
If philosophers want to probe to the bottom of this barely philosophical matter, let them meditate on the banquet of plato . 如果哲学家想对这个几乎不属于哲学范畴的概念追根寻源，就让他们回忆一下柏拉图的宴会吧！
It is in the seattle neighbourhoods, especially those on the hill-tops, that the conservation elements dwell . 就西雅图的邻里，尤其是山岗顶端那些邻里的情况来看，那里常是保守的、守法的、遵守道德规范的人居住的地方。
Judging method for reflectogram of commercial coal 商品煤反射率分布图的判别方法
