lean_workbook_plus_25060

⚠️ 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.

For $n=45$ example : all numbers from $1$ to $49$ , except $20,25,30,40$

Why this node was retired

The posted statement is

theorem lean_workbook_plus_25060 : ∀ n, n = 45 → (∀ k, k ∈ Finset.Icc 1 49 ∧ k ≠ 20 ∧ k ≠ 25 ∧ k ≠ 30 ∧ k ≠ 40)   :=  by sorry

The source only describes an example and its original problem is absent.

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

Proposed corrected statement

Define S={1,…,49}∖{20,25,30,40} and prove |S|=45, rather than claiming every natural belongs to that finite set. Recover any further property asked of the example.

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.