theorem investmentRate_pos {s₀ ψ τ : ℝ} (hs : 0 < s₀) (hψτ : ψ * τ < 1) : 0 < investmentRate s₀ ψ τ := by simp only [investmentRate] exact mul_pos hs (by linarith)
thesis/CESProofs/Macro/GrowthTax.lean:121
Growth and Dynamic Tax Revenue (Layer 4-5 of Macro Extension)