Fig. 2
From: A framework to find the logic backbone of a biological network
Example of a causal edge representation of a Boolean network. Blue edges represent necessary relationships, red edges represent sufficient relationships and the black edge represents a sufficient and necessary relationship. Node M1 (blue) is a mediator node. Node B is a signal (source node) while node D is an output node. The Boolean rules are: f A =B OR (NOT C); f C =B; f D =A OR (B AND C)