# articulation_points

From igraph v1.0.1
by Gabor Csardi

##### Articulation points of a graph

Articuation points or cut vertices are vertices whose removal increases the number of connected components in a graph.

- Keywords
- graphs

##### Usage

`articulation_points(graph)`

##### Arguments

- graph
The input graph. It is treated as an undirected graph, even if it is directed.

##### Details

Articuation points or cut vertices are vertices whose removal increases the number of connected components in a graph. If the original graph was connected, then the removal of a single articulation point makes it undirected. If a graph contains no articulation points, then its vertex connectivity is at least two.

##### Value

A numeric vector giving the vertex ids of the articulation points of the input graph.

##### See Also

`biconnected_components`

, `components`

,
`is_connected`

, `vertex_connectivity`

##### Examples

```
# NOT RUN {
g <- disjoint_union( make_full_graph(5), make_full_graph(5) )
clu <- components(g)$membership
g <- add_edges(g, c(match(1, clu), match(2, clu)) )
articulation_points(g)
# }
```

*Documentation reproduced from package igraph, version 1.0.1, License: GPL (>= 2)*

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