lean_workbook_plus_63717

Proved

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

Let $a,b,c\geq 0$ and $a+b+c>0 .$ Prove that \n

\frac{b}{a+2b+c}+\frac{ c}{a+b+2c} \leq \frac{2}{3}

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_63717 :  ∀ a b c : ℝ, a ≥ 0 ∧ b ≥ 0 ∧ c ≥ 0 ∧ a + b + c > 0 → b / (a + 2 * b + c) + c / (a + b + 2 * c) ≤ 2 / 3   :=  by sorry

Source

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

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