theorem
proved
tactic proof
intensityAtRung_strictly_decreasing
show as:
view Lean formalization →
formal statement (Lean)
57theorem intensityAtRung_strictly_decreasing (k : ℕ) :
58 intensityAtRung (k + 1) < intensityAtRung k := by
proof body
Tactic-mode proof.
59 rw [intensityAtRung_succ_ratio]
60 have hk : 0 < intensityAtRung k := intensityAtRung_pos k
61 have hphi_inv_lt_one : phi⁻¹ < 1 := by
62 have hphi_gt_one : (1 : ℝ) < phi := by
63 have := Constants.phi_gt_onePointFive; linarith
64 exact inv_lt_one_of_one_lt₀ hphi_gt_one
65 have : intensityAtRung k * phi⁻¹ < intensityAtRung k * 1 :=
66 mul_lt_mul_of_pos_left hphi_inv_lt_one hk
67 simpa using this
68