lean_workbook_plus_60367
Disproved⚠️ Retired — mistyped fractional exponent
The exponents
^(1/2),^(1/3)in the Lean statement below are natural-number division, not a real exponent, so they collapse to an integer power and the displayed radical is not what is being asserted. Do not import this node or use it as a dependency.
Prove that
Why this node was retired
The posted statement is
theorem lean_workbook_plus_60367 : (3 : ℝ)^(1/3) > (2 : ℝ)^(1/2) := by sorry
A numeric-literal exponent carrying no type ascription is elaborated at type ℕ (via HPow ℝ ℕ ℝ, Monoid.npow), and natural-number division truncates. Each occurrence therefore collapses:
^(1/2)→^0, so the radical is1for every base^(1/3)→^0, so the radical is1for every base
The recorded counterexample refutes the collapsed statement. It says nothing about the exercise displayed on this page, which is a different proposition.
What a faithful statement would require
Every fractional exponent must be given a real type, e.g. x ^ ((1 : ℝ) / 3) using Real.rpow, or be written with the intended root operation (Real.sqrt, or the signed real cube root where the radicand may be negative). Real powers also need their own domain hypotheses: rpow is only the intended root for a nonnegative base.
No corrected replacement node exists yet, and this target has no record in the public Prove2Me statement audit — the defect above was identified directly from the Lean text.
import Mathlib.Analysis.Complex.Basic
theorem lean_workbook_plus_60367 : (3 : ℝ)^(1/3) > (2 : ℝ)^(1/2) := by sorry