def escortCumulant3 (x : Fin J → ℝ) (ρ : ℝ) : ℝ := escortRawMoment x ρ 3 - 3 * escortRawMoment x ρ 2 * escortRawMoment x ρ 1 + 2 * escortRawMoment x ρ 1 ^ 3
thesis/CESProofs/Foundations/CumulantTower.lean:178
The Cumulant Tower: Higher-Order Bridges Between CES and Escort Statistics