theorem cesEigenvaluePerp_neg {J : ℕ} (hJ : 0 < J) {ρ : ℝ} (hρ : ρ < 1)
{c : ℝ} (hc : 0 < c) :
cesEigenvaluePerp J ρ c < 0 := by
simp only [cesEigenvaluePerp]
apply div_neg_of_neg_of_pos
· linarith
· exact mul_pos (Nat.cast_pos.mpr hJ) hcDiscrete-Time Stability of CES Tâtonnement (Edge of Stability)