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**NETWORK > REGIONS > BICOMPONENTS**

**PURPOSE **Finds all the cutpoints or articulation points and bi-components or blocks of a graph.

**DESCRIPTION **A cutpoint of a graph is a vertex whose removal increases the number of components these are also called articulation points. A non-separable graph is a graph that is connected non-trivially and has no cutpoints. A block or bicomponent of a graph is a maximal non-separable subgraph. The name bi-component reflects the fact that it requires the deletion of two vertices to disconnect it. Bi-components overlap, but a vertex that is in more than one bi-component it must be a cutpoint.

**PARAMETERS*** *

* ***Input dataset***:*

Name of file containing graph to be analyzed. Data type: Graph.

* ***(output) block by actor matrix:**(Default=BiComponents)

Name of file that will contain a block by actor incidence matrix. A 1 in column i row j means that node j is in bi-component i. This file is not displayed in the LOG FILE..

** (output) cutpoint dataset:**(Default=Cutpoints)

** **Name of file that contains a cutpoint indicator vector a 1 in row i indicates that i is a cutpoint.

**LOG FILE **Number of bi-components found.

List of bi-components, labeled - each bi-component is specified by the vertices it contains.

Cutpoint indicator vector

**TIMING **O(N^2).

**COMMENTS **None.

**REFERENCES **None.