Preferential attachment networks are a type of random network where new nodes are
connected to existing ones at random and are more likely to connect to those that
already have many connections. We investigate further a family of models introduced
by Antunović, Mossel and Rácz where each vertex in a preferential attachment
graph is assigned a type, based on the types of its neighbours. Instances of this type
of process where the proportions of each type present do not converge over time seem
to be rare.
Previous work found that a “rock-paper-scissors” setup where each new node’s
type was determined by a rock-paper-scissors contest between its two neighbours
does not converge. Here, two cases similar to that are considered, one which is like
the above but with an arbitrarily small chance of picking a random type and one
where there are four neighbours which perform a knockout tournament to determine
the new type.
These two new setups, despite seeming very similar to the rock-paper-scissors
model, do in fact converge, perhaps surprisingly.