“…If, additionally, φ is convex, then φ (s) ≥ 0 for s ∈ [α, β]. Furthermore, by assumption (19), the first factor under the integral on the right-hand side is also nonnegative. Therefore, the right-hand side of ( 20) is non-negative, so the left-hand side is as well, i.e., (18) holds.…”