theorem cesGeneralHessianQF_neg_semidef
{ρ : ℝ} (hρ : ρ < 1) {F : ℝ} (hF : 0 < F)
(P : Fin J → ℝ)
(hP_nn : ∀ j, 0 ≤ P j)
(hP_sum : ∑ j, P j = 1)
(x v : Fin J → ℝ) (hx : ∀ j, x j ≠ 0) :
cesGeneralHessianQF ρ F P x v ≤ 0 := by
rw [cesGeneralHessianQF_eq_neg_variance ρ F P x v hx]
have hvar := weighted_variance_nonneg P
(fun j => v j / x j) hP_nn hP_sum
have h1 : 0 < (1 - ρ) * F := mul_pos (by linarith) hF
nlinarithGeneral CES Hessian at Arbitrary Allocation