lean_workbook_plus_76409

Proved

by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)

Prove that $\frac{a^{2}}{4}+b^{2}+c^{2}-ab+ac-2bc \geq 0$ for all real numbers $a$ , $b$ , and $c$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_76409 (a b c : ℝ) : a^2 / 4 + b^2 + c^2 - a * b + a * c - 2 * b * c ≥ 0   :=  by sorry

Source