lean_workbook_plus_75839

Proved

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

Let $x,y\geq 0$ and $x+y^3=y^4+1.$ Prove that $y+x^3\leq x^4+1$

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_75839 (x y : ℝ) (hx : 0 ≤ x) (hy : 0 ≤ y) (h : x + y^3 = y^4 + 1) : y + x^3 ≤ x^4 + 1   :=  by sorry

Source