theorem curvatureK_abs_substitute (hJ : 2 ≤ J) {ρ : ℝ} (hρ : 1 < ρ) :
|curvatureK J ρ| = (ρ - 1) * (↑J - 1) / ↑J := by
rw [abs_of_neg (curvatureK_neg_substitute hJ hρ)]
simp only [curvatureK]; ringSubstitute Regime: The ρ > 1 Theory (Anti-Complementarity)