lean_workbook_plus_62323

Proved

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

f:\mathbb{R} \to \mathbb{R} $means every$ x $in$ \mathbb{R} $(domain) is assigned a value$ f(x) $which lies in$ \mathbb{R}$ (codomain)

Preamble

import Mathlib.Analysis.Complex.Basic

Formal statement

theorem lean_workbook_plus_62323 (f : ℝ → ℝ) : Set.range f = {y : ℝ | ∃ x : ℝ, y = f x}   :=  by sorry

Source