lean_workbook_plus_42650
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.
Express as a fraction and show that it equals 1.
Why this node was retired
The posted statement is
theorem lean_workbook_plus_42650 : (0.9 : ℝ) = 1 := by sorry
The repeating decimal 0.999… is replaced by the finite decimal 0.9.
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 the repeating decimal as ∑(n≥1)9/10^n, or the limit of its finite truncations, and prove it equals 1.
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_42650 : (0.9 : ℝ) = 1 := by sorry