`nwbridges`

Find bridges (ties whose removal disconnects the network)

Syntax

nwbridges
[netname]
[,
name(newnetname)
type(type)
nwreplace]


`name(newnetname)`	Save bridges as network; default = _bridges.
`type`(type)	Type of bridge; default = global
`nwreplace`	Overwrite network newnetname.

Description

A global bridge is a tie from node i to j if deleting the tie would make it impossible to reach node j from node i. A bridge is therefore essential to connect two nodes (or different parts of the network) with each other.

In contrast, a tie between nodes i and j is a local bridge if deleting the tie would increase the distance between i and j to a value strictly more than two.

The command saves all bridges as a new network newnetname.

Examples

. nwwebuse florentine, nwclear
. nwbridges flobusiness
. nwbridges flobusiness, type(local) nwreplace

Supported network types

Binary: yes (only) - bridge status is a structural property, tie values are ignored. Directed: yes - type() distinguishes local/global bridges and arcs vs. edges. Weighted: not applicable. Signed: not applicable. Two-mode: same as for the bipartite graph read as a one-mode network (valid; no mode-specific normalisation).

Stored results

Macros

r(name) name of the source network
r(directed) whether the source network is directed (true/false)
r(bridges) number of bridges found
r(bridges_type) the type() used (global/local/distance)

References

Burt, R. S. (1992). Structural Holes: The Social Structure of Competition. Cambridge: Harvard University Press.

nwbridges