lean_workbook_plus_8256

Proved

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

We know if $a>b>c>d,$ then $ad+bc<ac+bd<ab+cd$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_8256 (a b c d : ℝ) (h1 : a > b ∧ b > c ∧ c > d) : a * d + b * c < a * c + b * d ∧ a * c + b * d < a * b + c * d   :=  by sorry

Source

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

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