lean_workbook_plus_21335

Disproved

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

Prove that $\frac{ab}{a+b}+ \frac{bc}{b+c} \le \frac{(a+b)(b+c)}{(a+b)+(b+c)}$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_21335 : ∀ a b c : ℝ, (a * b) / (a + b) + (b * c) / (b + c) ≤ (a + b) * (b + c) / (a + b + (b + c))   :=  by sorry

Source