![Articulation Node | The Geography of Transport Systems](https://i0.wp.com/transportgeography.org/wp-content/uploads/articulation_node.png?resize=900%2C451&ssl=1)
By removing node 1 from graph A, we obtain graph B, which is connected. 1 is thus not an articulation node. If we remove node 4 from graph A, the result is an unconnected graph C where p=2 (two subgraphs). Node 4 is thus the only articulation node of graph A. Removing any other node does not create two separate subgraphs.