theorem aggregateOscillationEnergy_nonneg (e : NSectorEconomy N)
(ξ : Fin N → ℝ) :
0 ≤ aggregateOscillationEnergy e ξ := by
unfold aggregateOscillationEnergy
exact oscillationEnergy_nonneg (fun n => sectorEffectiveCurvature_nonneg e n) ξMultiplier-Cycle Duality in a Multi-Sector Economy