lean_workbook_plus_62379

Proved

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

If $x , y, z \in\ (0,1)$ and $xy+yz+zx=1$ then prove that : $x+y+z\leq2$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_62379 (x y z : ℝ) (h : x ∈ Set.Ioo 0 1 ∧ y ∈ Set.Ioo 0 1 ∧ z ∈ Set.Ioo 0 1 ∧ x * y + y * z + z * x = 1) :
  x + y + z ≤ 2   :=  by sorry

Source

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

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