theorem
proved
term proof
gap_decreasing
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formal statement (Lean)
58theorem gap_decreasing {N₁ N₂ : ℝ} (h₁ : 0 < N₁) (h_lt : N₁ < N₂) :
59 gapToCapacity N₂ < gapToCapacity N₁ := by
proof body
Term-mode proof.
60 unfold gapToCapacity
61 have h₂ : 0 < N₂ := lt_trans h₁ h_lt
62 have hp : 0 < phi := phi_pos
63 have hphi_N1 : 0 < phi * N₁ := mul_pos hp h₁
64 have hphi_N2 : 0 < phi * N₂ := mul_pos hp h₂
65 -- 1 / (phi * N₂) < 1 / (phi * N₁) since phi * N₁ < phi * N₂
66 have h_lt' : phi * N₁ < phi * N₂ := mul_lt_mul_of_pos_left h_lt hp
67 exact one_div_lt_one_div_of_lt hphi_N1 h_lt'
68
69/-- Doubling N halves the gap. -/