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A summary of the rules of replication in an urn model. Active chains are drawn as filled balls and inactive chains are white balls. (a) represents the action of selecting an active chain replicating following the simple replicator mechanism; (b) shows the replicating process of a hypercyclic replicator; (c) corresponds to the decay which, for the purpose of this work, is supposed to act equivalently in each replicator-type.
