lean_workbook_plus_68071

Proved

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

Since $a^{2}+1\geq 2a,\ b^{2}+1\geq 2b,\ c^{2}+1\geq 2c$ , we have $a^{2}+b^{2}+c^{2}+3\geq 2(a+b+c)\ \cdots [1]$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_68071 (a b c : ℝ) : a^2 + b^2 + c^2 + 3 ≥ 2 * (a + b + c)   :=  by sorry

Source