Figure 1.

Wiring diagram and state space of the Boolean network $F=(f_1,f_2,f_3)=(x_2\wedge \mathrm{\neg }{x}_3,x_3,\mathrm{\neg }{x}_1\wedge x_2)$. (a) The wiring diagram encodes the dependency between variables. Subnetworks are defined on the basis of the wiring diagram. For example, the subnetwork $F{|}_{\{x_2,x_3\}}(x_1,x_2,x_3)=(x_3,\mathrm{\neg }{x}_1\wedge x_2)$ is the restriction of F to {x₂, x₃} and contains external parameter x₁. (b) The state space is a directed graph with edges between all states and their images. This graph, therefore, encodes all possible trajectories and attractors. Here, F has two steady states, 000 and 011, and one limit cycle, (010, 101), so $\mathcal{A}(F)=\{000,011,$ $(010,101)\}$.