lean_workbook_plus_29444

⚠️ 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.

Evaluate $2000^3-1999\\cdot 2000^2-1999^2\\cdot 2000+1999^3$

Why this node was retired

The posted statement is

theorem lean_workbook_plus_29444 (x : ℤ) : 2000^3 - 1999 * 2000^2 - 1999^2 * 2000 + 1999^3 = 3999   :=  by sorry

The unrelated binder x:ℤ does not force the standalone numerical expression to use integer subtraction.

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

Proposed corrected statement

Explicitly evaluate the expression in ℤ or ℝ; its value3999 is correct there.

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.