lean_workbook_plus_47893

Proved

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

a(1-b)+b(1-c)+c(1-d)+d(1-a)\le2

for all $0\leq a,b,c,d\leq1.$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_47893 (a b c d : ℝ) (ha : 0 ≤ a ∧ a ≤ 1) (hb : 0 ≤ b ∧ b ≤ 1) (hc : 0 ≤ c ∧ c ≤ 1) (hd : 0 ≤ d ∧ d ≤ 1) : a * (1 - b) + b * (1 - c) + c * (1 - d) + d * (1 - a) ≤ 2   :=  by sorry

Source

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

View graph