Appendices A On the Commutativity Assumption We consider the problem f (x, θ) = 1 2 null Ax y 2 2 + θ x x 2 D null, with x

In this case, Assumption 2 is no longer verified. In this proof, we assume that t 1. We now compute its maximum value. This means there is only one maximum in the expression. In particular, this means that if hλ < 2, the bound decreases monotonically for t = 1, 2, . .