lean_workbook_plus_69423

⚠️ 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 $x,y,z \in \mathbb{N}$ such that $\frac{1}{x}+\frac{1}{y}+\frac{1}{z} <1$, prove that $\frac{1}{x}+\frac{1}{y}+\frac{1}{z} <\frac{41}{42}$

Why this node was retired

The posted statement is

theorem lean_workbook_plus_69423 (x y z : ℕ) (h : 1/x + 1/y + 1/z < 1) : 1/x + 1/y + 1/z < 41/42   :=  by sorry

Natural division collapses the fractions; additionally the source strict bound is false at (2,3,7), where the sum equals 41/42.

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

Proposed corrected statement

For positive integers and real division replace the conclusion by ≤41/42; prove the sharp bound and its equality cases.

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.