lean_workbook_plus_69322

⚠️ 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.

Show that the equation $a^2+b^2+c^2+d^2=a^2\cdot b^2\cdot c^2\cdot d^2$ has no solution in positive integers.

Why this node was retired

The posted statement is

theorem lean_workbook_plus_69322 : ¬∃ a b c d : ℤ, a^2 + b^2 + c^2 + d^2 = a^2 * b^2 * c^2 * d^2   :=  by sorry

Require a,b,c,d>0, exactly as in the prose; the zero integer tuple is then excluded by the intended domain.

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

Proposed corrected statement

Require a,b,c,d>0, exactly as in the prose; the zero integer tuple is then excluded by the intended domain.

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.