leanprover-community / leanprover-community/mathlib4
Missing `FunLike` instances for Quivers
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lean4-change-in-behaviour
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Description
In several category theory files, it is necessary to add instances of the form
instance instFunLike (X Y : BddOrdCat) : FunLike (X ⟶ Y) X (fun _ => Y) :=
show FunLike (BoundedOrderHom X Y) X (fun _ => Y) from inferInstance
where the category BddOrdCat and the type of Hom varies. Is it really intended that these have to be added manually for each category defined?
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 locating the category theory files and the existing FunLike instances for BddOrdCat and related Hom types. Determine whether a shared mechanism is intended to replace the manual instances; done requires an agreed approach and corresponding coverage across the affected categories.
Written by the indexing model from the issue text.
Assessment
- Domain
- tooling
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100