The Discrete Evolution Model of Bak and Sneppen is Conjugate to the Classical Contact Process

Two fundamental models of critical phenomena are connected. We show that the discrete Bak–Sneppen evolution model is conjugate to the classical contact process. This holds in discrete and continuous time, on all graphs and for random as well as for deterministic choice of neighbors. Thus the extensive theory for the contact process applies to the discrete Bak–Sneppen model, too.