On the Widom–Rowlinson Occupancy Fraction in Regular Graphs
On the Widom–Rowlinson Occupancy Fraction in Regular Graphs
We consider the Widom–Rowlinson model of two types of interacting particles on d -regular graphs. We prove a tight upper bound on the occupancy fraction, the expected fraction of vertices occupied by a particle under a random configuration from the model. The upper bound is achieved uniquely by unions of …