theorem
proved
tactic proof
predictability_threshold_band
show as:
view Lean formalization →
formal statement (Lean)
65theorem predictability_threshold_band :
66 0.11 < PredictabilityThreshold ∧ PredictabilityThreshold < 0.13 := by
proof body
Tactic-mode proof.
67 unfold PredictabilityThreshold
68 have hphi_ne : phi ≠ 0 := Constants.phi_ne_zero
69 rw [Cost.Jcost_eq_sq hphi_ne]
70 have h_lo : (1.61 : ℝ) < phi := Constants.phi_gt_onePointSixOne
71 have h_hi : phi < (1.62 : ℝ) := Constants.phi_lt_onePointSixTwo
72 have hpos : (0 : ℝ) < 2 * phi := by
73 have : (0 : ℝ) < phi := Constants.phi_pos
74 linarith
75 refine ⟨?lo, ?hi⟩
76 · rw [lt_div_iff₀ hpos]
77 nlinarith [h_lo, h_hi]
78 · rw [div_lt_iff₀ hpos]
79 nlinarith [h_lo, h_hi]
80