lean_workbook_plus_63136

Proved

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

$2b\ge a+c$ (1), $2c\ge b+d$ (2), $2d\ge c+a$ (3), $2a\ge d+b$ (4)

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_63136 (a b c d : ℝ) (h1 : 2 * b ≥ a + c) (h2 : 2 * c ≥ b + d) (h3 : 2 * d ≥ c + a) (h4 : 2 * a ≥ d + b) : a + b + c + d ≤ 2 * (a + b) ∧ a + b + c + d ≤ 2 * (c + d) ∧ a + b + c + d ≤ 2 * (b + d) ∧ a + b + c + d ≤ 2 * (a + c)   :=  by sorry

Source

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

View graph