theorem
proved
tactic proof
edge_deviation_small
show as:
view Lean formalization →
formal statement (Lean)
68theorem edge_deviation_small {r : ℝ} (hr : 0 < r) {δ : ℝ} (hδ : 0 ≤ δ)
69 (hδ_small : δ ≤ 1) (hJ : Jcost r ≤ δ) : (r - 1) ^ 2 ≤ 8 * δ := by
proof body
Tactic-mode proof.
70 have h := edge_deviation_bound hr hδ hJ
71 calc (r - 1) ^ 2 ≤ 4 * δ * (1 + δ) := h
72 _ ≤ 4 * δ * (1 + 1) := by nlinarith
73 _ = 8 * δ := by ring
74
75/-- Absolute deviation bound: |r - 1| ≤ √(8δ) for δ ≤ 1. -/