theorem perCapitaSurplus_alt {J : ℝ} (hJ : J ≠ 0) (ρ : ℝ) : perCapitaSurplus J ρ = (1 - ρ) * (J⁻¹ - (J ^ 2)⁻¹) := by simp only [perCapitaSurplus] field_simp
thesis/CESProofs/EntryExit/Calculus.lean:167
Paper 1c: Formal Calculus on K(J) and V(J)