R igraph manual pages

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Burt's constraint

Description

Given a graph, `constraint` calculates Burt's constraint for each vertex.

Usage

```constraint(graph, nodes = V(graph), weights = NULL)
```

Arguments

 `graph` A graph object, the input graph. `nodes` The vertices for which the constraint will be calculated. Defaults to all vertices. `weights` The weights of the edges. If this is `NULL` and there is a `weight` edge attribute this is used. If there is no such edge attribute all edges will have the same weight.

Details

Burt's constraint is higher if ego has less, or mutually stronger related (i.e. more redundant) contacts. Burt's measure of constraint, C[i], of vertex i's ego network V[i], is defined for directed and valued graphs,

C[i] = sum( [sum( p[i,j] + p[i,q] p[q,j], q in V[i], q != i,j )]^2, j in V[i], j != i).

for a graph of order (ie. number of vertices) N, where proportional tie strengths are defined as

p[i,j]=(a[i,j]+a[j,i]) / sum(a[i,k]+a[k,i], k in V[i], k != i),

a[i,j] are elements of A and the latter being the graph adjacency matrix. For isolated vertices, constraint is undefined.

Value

A numeric vector of constraint scores

Author(s)

Jeroen Bruggeman (https://sites.google.com/site/jebrug/jeroen-bruggeman-social-science) and Gabor Csardi csardi.gabor@gmail.com

References

Burt, R.S. (2004). Structural holes and good ideas. American Journal of Sociology 110, 349-399.

Examples

```
g <- sample_gnp(20, 5/20)
constraint(g)

```

[Package igraph version 1.2.4.1 Index]