lean_workbook_plus_9903
Disproved⚠️ Retired — specification defect
The Lean statement below does not encode the problem shown on this page, so its
Disprovedstatus carries no information about that problem. Do not import this node or use it as a dependency.
What is the value of
Why this node was retired
The posted statement is
theorem lean_workbook_plus_9903 : (2^2-2)-(3^2-3)+(4^2-4) = 0 := by sorry
Natural subtraction and the invented zero answer both change the computation.
The recorded counterexample refutes the statement as encoded. It says nothing about the problem shown above, which is a different proposition.
Proposed corrected statement
Evaluate the expression in ℤ or ℝ and give the answer8.
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.
import Mathlib.Analysis.Complex.Basic
theorem lean_workbook_plus_9903 : (2^2-2)-(3^2-3)+(4^2-4) = 0 := by sorry