lean_workbook_plus_45403

Disproved

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

prove that \n ${\frac {a}{b}}+{\frac {b}{c}}+{\frac {c}{d}}+{\frac {d}{a}}+{\frac {253}{10}}\,{\frac {ab+bc+cd+ad+ac+bd}{ \left( a+b+c+d \right) ^{2}}}\geq {\frac {1079}{80}}$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_45403 : ∀ a b c d : ℝ, (a / b + b / c + c / d + d / a + 253 / 10 * (a * b + b * c + c * d + d * a + a * c + b * d) / (a + b + c + d) ^ 2) ≥ 1079 / 80   :=  by sorry

Source

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

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