lean_workbook_plus_37083

Disproved

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

prove $\frac{1}{{{\left( 1+x\right)}^{3}}}+\frac{1}{{{\left( 1+y\right)}^{3}}}+\frac{1}{{{\left( 1+z\right)}^{3}}}\ge\frac{3}{8}$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_37083 : ∀ x y z : ℝ, (1 / (1 + x) ^ 3 + 1 / (1 + y) ^ 3 + 1 / (1 + z) ^ 3) ≥ 3 / 8   :=  by sorry

Source