lean_workbook_plus_12140

Proved

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

If $a,b,c,d$ are positive real numbers then prove that $(1+a^4)(1+b^4)(1+c^4)(1+d^4)\ge (1+(abcd)^4)$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_12140 (a b c d : ℝ) (ha : 0 < a) (hb : 0 < b) (hc : 0 < c) (hd : 0 < d) : (1 + a^4) * (1 + b^4) * (1 + c^4) * (1 + d^4) ≥ 1 + (a * b * c * d)^4   :=  by sorry

Source

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

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