theorem bridge_W_uniform_depreciation
{P_cycle sigma beta_n : ℝ} (hP : 0 < P_cycle) (hsig : 0 < sigma)
(hb : 0 < beta_n) :
0 < P_cycle / (sigma * beta_n) := by
exact div_pos hP (mul_pos hsig hb)Theorems 7-8, Propositions 5 and 7, Corollary 3: