lean_workbook_plus_31539

Proved

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

Since $a,b,c,d \in [1;3]$ , then $(a-1)(b-1)(c-1) \ge 0$ and $(3-a)(3-b)(3-c) \ge 0$ .

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_31539 (a b c d : ℝ) (hab : 1 ≤ a ∧ a ≤ 3) (hbc : 1 ≤ b ∧ b ≤ 3) (hcd : 1 ≤ c ∧ c ≤ 3) : (a - 1) * (b - 1) * (c - 1) ≥ 0 ∧ (3 - a) * (3 - b) * (3 - c) ≥ 0   :=  by sorry

Source

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

View graph