Figure 4. Power-law product rule for integration of two input signals in an FCD system, where both inputs bind the same receptor with different number of sites.

(A) Let L₁ have one binding site, and L₂ have two sites. Response to simultaneous steps of L₁ and L₂ of folds F₁ and F₂ is dependent only on . Thus, steps with F₁ = 4 and F₂ = 2 shows the same output dynamics as two steps with F₁ = 16 and F₂ = 1 or two steps of F₁ = 1 and F₂ = 4, since in all cases (B) Linear equi-response contours in the (log F₁, log F₂) plane. With increasing values of - amplitude rises (red to yellow) and response time decreases (yellow to red).