Resumen
Three computer algorithms are presented. One reduces a network ??
N
to its interior, I
I
. Another counts all the triangles in a network, and the last randomly generates networks similar to ??
N
given just its interior I
I
. However, these algorithms are not the usual numeric programs that manipulate a matrix representation of the network; they are set-based. Union and meet are essential binary operators; contained_in is the basic relational comparator. The interior I
I
is shown to have desirable formal properties and to provide an effective way of revealing ?communities? in social networks. A series of networks randomly generated from I
I
is compared with the original network, ??
N
.