This term adds one network statistic to the
model for each element in k . The \(i\) th such statistic counts the
number of distinct k[i] -instars in the network, where a
\(k\) -instar is defined to be a node \(N\) and a set of \(k\)
different nodes \(\{O_1, \dots, O_k\}\) such that the ties
\((O_j{\rightarrow}N)\) exist for \(j=1, \dots, k\) .
This term can only be used for directed
networks; for undirected networks see kstar . Note that
istar(1) is equal to both ostar(1) and edges .
# binary: istar(k, attr=NULL, levels=NULL)a vector of distinct integers
a vertex attribute specification; if attr is
specified, then the count is over the instances where all nodes
involved have the same value of the attribute. levels specified
which values of attr are included in the count. (See Specifying
Vertex attributes and Levels
(?nodal_attributes) for details.)
ergmTerm for index of model terms currently visible to the package.
ergm:::.formatTermKeywords("ergmTerm", "istar", "subsection")