“…It follows from properties of f ( z ) function ( S ‐shaped graph, monotonicity, and boundedness) that Equation has at most 3 roots for any positive θ , w . For the specific sigmoidal function , the case n = 2 was studied in Atslega et al, and the general case of arbitrary n was investigated in Brokan and Sadyrbaev . It was proved that there exists decomposition of the first quadrant of the parameter ( μ , θ )‐plane in 2 disjoint sets separated by a simple curve so that for parameters in the first set, there is exactly 1 critical point of the type stable node, and for parameters in the second set, there are exactly 3 critical points of the type stable node (2 side points), and the remaining (middle) point is a saddle.…”