by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)
(a2+b2)2≥(a+b+c)(a+b−c)(b+c−a)(c+a−b)⟺ \n\n (a2+b2−c2)2+(a2−b2)2≥0 with equality iff 1∣a∣=1∣b∣=2∣c∣
Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_54808 {a b c : ℝ} :
(a^2 + b^2)^2 ≥ (a + b + c) * (a + b - c) * (b + c - a) * (c + a - b) ↔
(a^2 + b^2 - c^2)^2 + (a^2 - b^2)^2 ≥ 0 := by sorry