theorem escortFisherQF_zero_radial (ρ : ℝ) (P x : Fin J → ℝ)
(hx : ∀ j, x j ≠ 0) (hP : ∑ j, P j = 1) :
escortFisherQF ρ P x x = 0 := by
simp only [escortFisherQF]
have h1 : ∀ k : Fin J, x k / x k = 1 := fun k => div_self (hx k)
simp_rw [h1, one_pow, mul_one, hP, one_pow, sub_self, mul_zero]General CES Hessian at Arbitrary Allocation