theorem escortRawMoment_hasDerivAt [NeZero J]
(x : Fin J → ℝ) (hx : ∀ j, 0 < x j) (ρ : ℝ) (n : ℕ) :
HasDerivAt (fun p => escortRawMoment x p n)
(escortRawMoment x ρ (n + 1) -
escortRawMoment x ρ n * escortRawMoment x ρ 1) ρ := by
unfold escortRawMoment
have hZ := ne_of_gt (escortPartitionZ_pos x hx ρ)
have hquot := (escortPartitionZn_hasDerivAt x hx ρ n).div
(escortPartitionZ_hasDerivAt x hx ρ) hZ
refine hquot.congr_deriv ?_
rw [← escortPartitionZn_one]
field_simpThe Cumulant Tower: Higher-Order Bridges Between CES and Escort Statistics