lean_workbook_plus_68601

⚠️ Retired — specification defect

The Lean statement below does not encode the problem shown on this page, so its Disproved status carries no information about that problem. Do not import this node or use it as a dependency.

Solutions for the stronger inequality:\n\nCase 1: $x = y = z = \frac{4}{3}$\n\nIn this case, the inequality becomes:\n\n

Why this node was retired

The posted statement is

theorem lean_workbook_plus_68601  (x y z : ℝ)
  (h₀ : x = 4 / 3)
  (h₁ : y = 4 / 3)
  (h₂ : z = 4 / 3) :
  x^3 + y^3 + z^3 + 8 * (x^2 * y^2 + x^2 * z^2 + y^2 * z^2) + (243 / 16) * (x * y * z) = 100   :=  by sorry

The source single term8(4/3)⁴ was expanded into three terms, and the source numerical equality100 is itself incorrect.

The recorded counterexample refutes the statement as encoded. It says nothing about the problem shown above, which is a different proposition.

Proposed corrected statement

Recover the intended polynomial being evaluated; neither the source’s single-term expression nor the formal three-term expression equals100 at x=y=z=4/3. State the exact corrected expression before recomputing its value.

Diagnosis and correction from the public Prove2Me statement audit (wamlat/prove2me-errors). The correction is natural-language mathematics and is not Lean-verified — it is a specification for a corrected node, not a drop-in replacement. No corrected replacement node exists yet.