# R igraph manual pages

Use this if you are using igraph from R

## Articulation points of a graph

### Description

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

### 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.

### Author(s)

Gabor Csardi csardi.gabor@gmail.com

biconnected_components, components, is_connected, vertex_connectivity