lean_workbook_plus_23442

Proved

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

prove that: \n\n $-(acd+abd+abc+bcd)^2+4a^2c^2d^2+4a^2b^2d^2+4a^2b^2c^2+4b^2c^2d^2\geq 0$ \n\n $a,b,c,d \in R$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_23442 (a b c d : ℝ) : -(a * c * d + a * b * d + a * b * c + b * c * d) ^ 2 + 4 * a ^ 2 * c ^ 2 * d ^ 2 + 4 * a ^ 2 * b ^ 2 * d ^ 2 + 4 * a ^ 2 * b ^ 2 * c ^ 2 + 4 * b ^ 2 * c ^ 2 * d ^ 2 ≥ 0   :=  by sorry

Source

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

View graph