lean_workbook_plus_8898

Proved

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

$\sum_{cyc}\frac{2-a}{2+a}\geq\frac{15}{7} \Leftrightarrow$ $\sum_{cyc}\frac{4}{2+a}\geq\frac{36}{7}$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_8898 {a b c : ℝ} (ha : 0 < a) (hb : 0 < b) (hc : 0 < c) : (2 - a) / (2 + a) + (2 - b) / (2 + b) + (2 - c) / (2 + c) ≥ 15 / 7 ↔ 4 / (2 + a) + 4 / (2 + b) + 4 / (2 + c) ≥ 36 / 7   :=  by sorry

Source

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

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