lean_workbook_plus_19717

⚠️ 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.

Subtract $11010_2$ from $10111_2$ in binary form.

Why this node was retired

The posted statement is

theorem lean_workbook_plus_19717 : 10111 - 11010 = 1001   :=  by sorry

Binary numerals were read as decimal naturals and signed subtraction became truncated.

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

Proposed corrected statement

Interpret10111₂=23 and11010₂=26 as integers; subtract to obtain−3=−11₂. Do not assert the unsupported binary result1001₂.

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.