theorem fragility_at_critical {Tstar1 Tstar2 : ℝ}
(hTs1 : 0 < Tstar1) (_hTs2 : 0 < Tstar2) (h : Tstar1 < Tstar2) :
institutionalMargin Tstar1 Tstar1 = 0 ∧
0 < institutionalMargin Tstar1 Tstar2 := by
constructor
· -- At T = T*₁: margin₁ = max(0, 1 - 1) = 0
simp [institutionalMargin, div_self (ne_of_gt hTs1)]
· -- At T = T*₁: margin₂ = max(0, 1 - T*₁/T*₂) > 0 since T*₁ < T*₂
simp only [institutionalMargin]
apply lt_max_of_lt_right
have hlt : Tstar1 / Tstar2 < 1 := by
rw [div_lt_one (by linarith)]
exact h
linarithInstitutional Reform Equivalence, Adjustment Timescale, and Fragility Ordering