lean_workbook_plus_11415

Proved

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

For positive reals $x,y,z$ prove that $\sum \frac {2}{x + y} \ge \frac{9}{x+y+z}$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_11415 (x y z : ℝ) (hx : 0 < x) (hy : 0 < y) (hz : 0 < z) : (2 / (x + y) + 2 / (y + z) + 2 / (z + x)) ≥ 9 / (x + y + z)   :=  by sorry

Source

https://huggingface.co/datasets/internlm/Lean-Workbook

View graph