| In graph theory, a path in a graph is a finite or infinite sequence of edges which joins a sequence of vertices which, by most definitions, are all distinct (and since the vertices are distinct, so are the edges). A directed path (sometimes called dipath) in a directed graph is a finite or infinite sequence of edges which joins a sequence of distinct vertices, but with the added restriction that the edges be all directed in the same direction. | | In graph theory, a path in a graph is a finite or infinite sequence of edges which joins a sequence of vertices which, by most definitions, are all distinct (and since the vertices are distinct, so are the edges). A directed path (sometimes called dipath) in a directed graph is a finite or infinite sequence of edges which joins a sequence of distinct vertices, but with the added restriction that the edges be all directed in the same direction. |
− | 在'''<font color="#ff8000">图论 Graph Theory</font>'''中,图中的'''<font color="#ff8000">路径 Path</font>'''是一个有限或无限的边序列,这些边连接着一系列顶点,这些顶点在大多数定义中都是不同的(因为顶点是不同的,所以边也是不同的)。'''<font color="#ff8000">有向图 Directed Graph</font>'''中的有向路径(有时称为dipath)是一个有限或无限的边序列,它连接一系列不同的顶点,但附加的条件是所有的边都方向相同。 | + | 在'''<font color="#ff8000">图论 Graph Theory</font>'''中,图中的'''<font color="#ff8000">路径 Path</font>'''是一个有限或无限的边序列,这些边连接着一系列顶点,这些顶点在大多数定义中都是不同的(又因为这些顶点是不同的,所以图中的边也是不同的)。'''<font color="#ff8000">有向图 Directed Graph</font>'''(有时也称为dipath)中的有向路径,在具有附加条件:所有的边都方向相同时是一个有限或无限的边序列,它连接一系列不同的顶点。 |
| Let be a graph. A finite walk is a sequence of edges for which there is a sequence of vertices such that ϕ(e<sub>i</sub>) = {v<sub>i</sub>, v<sub>i + 1</sub>} for . is the vertex sequence of the walk. This walk is closed if v<sub>1</sub> = v<sub>n</sub>, and open else. An infinite walk is a sequence of edges of the same type described here, but with no first or last vertex, and a semi-infinite walk (or ray) has a first vertex but no last vertex. | | Let be a graph. A finite walk is a sequence of edges for which there is a sequence of vertices such that ϕ(e<sub>i</sub>) = {v<sub>i</sub>, v<sub>i + 1</sub>} for . is the vertex sequence of the walk. This walk is closed if v<sub>1</sub> = v<sub>n</sub>, and open else. An infinite walk is a sequence of edges of the same type described here, but with no first or last vertex, and a semi-infinite walk (or ray) has a first vertex but no last vertex. |
− | 让我们以一个图为例{{nowrap|1=''G'' = (''V'', ''E'', ''ϕ'')}} 。有限步道是一系列的边{{nowrap|(''e''<sub>1</sub>, ''e''<sub>2</sub>, …, ''e''<sub>''n'' − 1</sub>)}},其顶点序列{{nowrap|(''v''<sub>1</sub>, ''v''<sub>2</sub>, …, ''v''<sub>''n''</sub>)}}。 {{nowrap begin}}''ϕ''(''e''<sub>''i''</sub>) = {''v''<sub>''i''</sub>, ''v''<sub>''i'' + 1</sub>}{{nowrap end}}对于{{nowrap|1=''i'' = 1, 2, …, ''n'' − 1}}. {{nowrap|(''v''<sub>1</sub>, ''v''<sub>2</sub>, …, ''v''<sub>''n''</sub>)}} 是移动的顶点序列。如果 {{nowrap begin}}''v''<sub>1</sub> = ''v''<sub>''n''</sub>{{nowrap end}} ,则此步道关闭,反之则打开。一个无限步道是一系列的边,它们的类型与这里描述的相同,但是没有起点或终点,而一个半无限步道(或光线)有起点,但是没有终点。
| + | 以一个图为例{{nowrap|1=''G'' = (''V'', ''E'', ''ϕ'')}} 。有限步道是一系列的边{{nowrap|(''e''<sub>1</sub>, ''e''<sub>2</sub>, …, ''e''<sub>''n'' − 1</sub>)}},其顶点序列{{nowrap|(''v''<sub>1</sub>, ''v''<sub>2</sub>, …, ''v''<sub>''n''</sub>)}}。 {{nowrap begin}}''ϕ''(''e''<sub>''i''</sub>) = {''v''<sub>''i''</sub>, ''v''<sub>''i'' + 1</sub>}{{nowrap end}}对于{{nowrap|1=''i'' = 1, 2, …, ''n'' − 1}}. {{nowrap|(''v''<sub>1</sub>, ''v''<sub>2</sub>, …, ''v''<sub>''n''</sub>)}} 是移动的顶点序列。如果 {{nowrap begin}}''v''<sub>1</sub> = ''v''<sub>''n''</sub>{{nowrap end}} ,则此步道封闭,反之则开放。一个无限步道是由一系列的边组成的,它们的类型与这里描述的相同,但没有起点或终点,而一个半无限步道(或光线)有起点但是没有终点。 |