leanprover-community / leanprover-community/mathlib4
Use `Pairwise` in `Set.iUnionLift` and `Set.liftCover`
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Description
In both cases, the condition is trivial for i = j, so we can require it Pairwise.
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
Locate the definitions of Set.iUnionLift and Set.liftCover in the mathlib4 source and read their current conditions. Update both cases so the condition is expressed with Pairwise, including the trivial i = j case, and verify that the affected proofs still compile.
Written by the indexing model from the issue text.
Assessment
- Domain
- tooling
- Issue type
- Refactor
- Difficulty
- 2/5
- Estimated time
- 1-3 hours
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 48/100