lean_workbook_plus_21666

Proved

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

Note that for all $0\le y\le1$ , \n

12 y^5 - 30 y^4 + 40 y^3 - 30 y^2 + 12 y + 3=5-2y^6+2(y-1)^6\ge3

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_21666 : ∀ y : ℝ, y ∈ Set.Icc 0 1 → 12*y^5 - 30*y^4 + 40*y^3 - 30*y^2 + 12*y + 3 ≥ 3   :=  by sorry

Source