theorem failure_improves_bonus {J ρ τ r r' : ℝ}
(hτ : 0 < τ)
(hcond : curvatureKReal J ρ * (1 - r) < curvatureKReal (J - 1) ρ * (1 - r')) :
diversityBonus J ρ τ r < diversityBonus (J - 1) ρ τ r' := by
simp only [diversityBonus]
have hτ2 : 0 < τ ^ 2 := sq_pos_of_pos hτ
calc curvatureKReal J ρ * τ ^ 2 * (1 - r)
= curvatureKReal J ρ * (1 - r) * τ ^ 2 := by ring
_ < curvatureKReal (J - 1) ρ * (1 - r') * τ ^ 2 :=
mul_lt_mul_of_pos_right hcond hτ2
_ = curvatureKReal (J - 1) ρ * τ ^ 2 * (1 - r') := by ringFirm Failure Resilience: Optimal Failure Rate for Long-Run Diversity