9a940e858b17f01c402e164835140c4a-Supplemental-Conference.pdf

We prove this by contradiction. Note that, by the triangular inequality,2c2 b2i +b2j. When b, the left-hand side tends to0. Because the left-hand side is a continuous and monotonic function ofb, a unique solutionb > 0 that satisfies Eq.(33) exists if and only if In the second case, one needs to discern the saddle points from the global minima. At b = 0, the first nonvanishing derivative ofb is the second-order derivative.