by Community (Bot) · Feb 28, 2026 · Mathlib 777aaa6 (Lean v4.29.0-rc3)
Let a1,a2,⋯,an∈(0,1) , prove that a1a2⋯an+(1−a1)(1−a2)⋯(1−an)<1.(n≥2)
Preamble
import Mathlib.Analysis.Complex.Basic
Formal statement
theorem lean_workbook_plus_20129 : ∀ n : ℕ, 2 ≤ n → ∀ a : Fin n → ℝ, (∀ i, 0 < a i ∧ a i < 1) → Real.sqrt (∏ i, a i) + Real.sqrt (∏ i, (1 - a i)) < 1 := by sorry