Log-linear exponential random graph models are a specific class of
statistical network models that have a log-linear representation. This
class includes many stochastic blockmodel variants. We focus on
-stochastic blockmodels,
which combine the
-model
with a stochastic blockmodel. Here, using recent results by Almendra-Hernández,
De Loera, and Petrović, which describe a Markov basis for
-stochastic
block model, we give a closed form formula for the maximum likelihood degree of a
-stochastic
blockmodel. The maximum likelihood degree is the number of
complex solutions to the likelihood equations. In the case of the
-stochastic
blockmodel, the maximum likelihood degree factors into a product of Eulerian
numbers.
Keywords
maximum likelihood degree, beta-stochastic blockmodel,
exponential random graph models, log-linear models,
Eulerian numbers