theorem diversityWelfareLoss_eq_zero_iff {J Jstar : ℝ}
(hJ : 0 < J) (hJs : 0 < Jstar) :
diversityWelfareLoss J Jstar = 0 ↔ J = Jstar := by
simp only [diversityWelfareLoss]
rw [welfareDistanceFn_eq_zero_iff (div_pos hJ hJs)]
constructor
· intro h; linarith [div_eq_one_iff_eq (ne_of_gt hJs) |>.mp h]
· intro h; rw [h, div_self (ne_of_gt hJs)]## Welfare with Endogenous J (merged from EntryExitWelfare.lean)