lean-ja / lean-ja/lean-by-example
with_unfolding_all と [reducible] 属性を付与するのは違う
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コード例
- Dominant language
- Lean
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Description
def NaturalNumber := Nat
-- エラー
#check (by with_unfolding_all infer_instance : Repr NaturalNumber)
attribute [reducible] NaturalNumber
-- エラーにならない
#check (by infer_instance : Repr NaturalNumber)
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the two #check examples from the issue in a Lean environment and compare instance synthesis with and without the [reducible] attribute. Trace how with_unfolding_all and reducibility affect the examples, then document the distinction and why the results differ.
Written by the indexing model from the issue text.
Assessment
- Domain
- compilers
- Issue type
- Documentation
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100