lean_workbook_plus_13062

Disproved

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

Assuming $f(x) < x$ for all $x$ in (0,1), derive a contradiction to the given hypothesis.

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_13062 (f : ℝ → ℝ) (hf: ∀ x ∈ Set.Ioo 0 1, f x < x) : False   :=  by sorry

Source