CategoryAnswerLinter.lean`

Explanation legend Lean4 Domain Explanation Language (L4DEL)

L4DEL explanations are a separate layer. They do not change the Lean source. Intuition is explanatory prose; numbered items are a reading path; sources link the wording back to evidence.

L4DEL: Lean4 Domain Explanation Language

Annotation provenance. This overlay contains 10 curated AI-written annotations and 7190 mechanical source-derived annotations. They have not been human-reviewed as explanations; treat them as unverified and not mathematical authority. Retained generation history: The 71 original curated annotations were produced in a Claude Sonnet 5.5 session at medium effort; Claude Opus 5.5 is recorded in that session as the advisor model, not the direct author. The bulk source-derived expansion was generated mechanically from pinned source comments by tooling developed in a GPT-5.6 Sol session at ultra reasoning; GPT-5.6 Sol did not originate the quoted source prose. On 2026-10-17 the mechanically generated source-comment annotations of the Formal Conjectures, Carleson, FLT, PFR, CompFiles, Mathematics in Lean and Theorem Proving in Lean overlays were regenerated by the same generator after three corrections made in a Claude Sonnet 5.5 session: titles no longer cut a sentence inside mathematics or end on a dangling word, workflow markers are removed from the quoted prose, and declaration names follow the scanner's namespace resolution. The boilerplate step line was dropped, and comments that were only a row of dashes no longer yield annotations. No new prose was written and no human review is claimed.

Credit: The upstream authors and contributors retain credit for the project and mathematics. lean4-explainer only renders their pinned source and adds the separately disclosed explanation layer.

Project sources: Pinned project documentation, Formal Conjectures paper, arXiv v1

5 declarations, 4 contain sorry, 0 declared as axioms

Imports (2)

theorem CategoryAnswerLinter.flagged_solved_answer_sorry A solved problem should not leave its answer unfilled sorry line 36 source
Source documentation
A solved problem should not leave its answer unfilled.

depends on sorry (Lean reported 4 error(s) in this file) what this means
Statement uses: Iff, True, Eq, Nat, HAdd.hAdd, OfNat.ofNat
Proof uses: sorryAx, Lean.Name, Bool.false, Lean.Name.num, Lean.Name.str, Lean.Name.anonymous
6 instances, coercions and auxiliary constants left out.

Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
```
theorem flagged_solved_answer_sorry : answer(sorry) ↔ 1 + 1 = 2 := by
…
```
theorem CategoryAnswerLinter.flagged_ascribed_answer_sorry The sorry is still a placeholder when it carries a type ascription sorry line 47 source
Source documentation
The sorry is still a placeholder when it carries a type ascription.

depends on sorry (Lean reported 4 error(s) in this file) what this means
Statement uses: Eq, Nat, sorryAx, Lean.Name, Bool.false, Lean.Name.num, Lean.Name.str, Lean.Name.anonymous, OfNat.ofNat
2 instances, coercions and auxiliary constants left out.

Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
```
theorem flagged_ascribed_answer_sorry : answer((sorry : Nat)) = 2 := by
…
```
theorem CategoryAnswerLinter.flagged_let_answer_sorry An answer bound by a let is flagged too sorry line 58 source
Source documentation
An answer bound by a let is flagged too.

depends on sorry (Lean reported 4 error(s) in this file) what this means
Statement uses: Nat, sorryAx, Bool.false, LT.lt, OfNat.ofNat
Proof uses: Lean.Name, Lean.Name.num, Lean.Name.str, Lean.Name.anonymous
4 instances, coercions and auxiliary constants left out.

Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
```
theorem flagged_let_answer_sorry :
    let c : Nat := answer(sorry)
…
```
Mentions: c
theorem CategoryAnswerLinter.not_flagged_explicit_answer A solved problem with an explicit answer is fine line 66 source
Source documentation
A solved problem with an explicit answer is fine.
```
theorem not_flagged_explicit_answer : answer(True) ↔ 1 + 1 = 2 := by
…
```
theorem CategoryAnswerLinter.not_flagged_open_answer_sorry An open problem may leave its answer unfilled sorry line 72 source
Source documentation
An open problem may leave its answer unfilled.

depends on sorry (Lean reported 4 error(s) in this file) what this means
Statement uses: Iff, True, Eq, Nat, HAdd.hAdd, OfNat.ofNat
Proof uses: sorryAx, Lean.Name, Bool.false, Lean.Name.num, Lean.Name.str, Lean.Name.anonymous
6 instances, coercions and auxiliary constants left out.

Tactic trace: 1 steps
Open to load the checked before-and-after goal states.
```
theorem not_flagged_open_answer_sorry : answer(sorry) ↔ 1 + 1 = 2 := by
…
```