Fig. 3
From: A comparative study of qualitative and quantitative dynamic models of biological regulatory networks
Dynamic analysis of an XNOR gate. a An XNOR gate and the corresponding equations and b state transition graphs for Boolean, hybrid, and Hill-type models. Both nodes A and B have the same Boolean equations, and similar corresponding hybrid and Hill equations; so only one is shown. The left or right binary digit of the node identifier indicates the state of A or B, respectively. The black-filled node in the Hybrid and Hill-type state spaces represents a threshold-dependent, real-valued fixed point