Existence of a fixed point for the weight dynamics.

<p>(A) Curves of the zeros of (39) for weights in the case of positively correlated inputs. The two curves have an intersection point, as the equilibrium curve for in red spans all , while that for in blue spans all . The arrows indicate the signs of the derivatives and in each quadrant (red and blue, resp.). (B) Similar to A with negative input correlations, for which the curves do not intersect.