boundary_expansion#

boundary_expansion(G, S)[source]#

Returns the boundary expansion of the set S.

The boundary expansion is the quotient of the size of the node boundary and the cardinality of S. [1]

Parameters:
GNetworkX graph
Scollection

A collection of nodes in G.

Returns:
number

The boundary expansion of the set S.

References

[1]

Vadhan, Salil P. “Pseudorandomness.” Foundations and Trends in Theoretical Computer Science 7.1–3 (2011): 1–336. <https://doi.org/10.1561/0400000010>