lean_workbook_plus_4859

⚠️ 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.

If three white rooks are on different rows and columns, then there are only 9 places for the black rooks to be placed. So for the white rooks, there are $36 * 25 * 16$ ways for then to be placed and then for the black rooks, there will be $9 * 8 * 7$ ways for them to be placed.

Why this node was retired

The posted statement is

theorem lean_workbook_plus_4859 : 36 * 25 * 16 * (9 * 8 * 7) = 1920000   :=  by sorry

The inserted arithmetic product value is wrong; the source fragment itself does not give that value.

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

Proposed corrected statement

Compute36·25·16·9·8·7=7257600. If counting indistinguishable rooks, separately justify any factorial divisors from the intended configuration model.

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.