lean_workbook_plus_45492

Proved

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

For reals $a\geq b \geq c \geq d \geq 0$ with $a^2+b^2+c^2+d^2=1$ \nProve that $a+b \geq 1\geq c+d$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_45492 (a b c d : ℝ) (h : a ≥ b ∧ b ≥ c ∧ c ≥ d ∧ d ≥ 0) (h2: a^2 + b^2 + c^2 + d^2 = 1) : a + b ≥ 1 ∧ 1 ≥ c + d   :=  by sorry

Source

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

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