leanprover-community / leanprover-community/mathlib4
Add `reassoc` for `LinearMap`
Nobody has claimed this yet.
- Dominant language
- Lean
- Stars
- 4.2k
- Forks
- 1.7k
- PR merge metrics
- No merged PRs in 30d
Description
Add a reassoc attribute for LinearMap lemmas so that we don't need to reassociate back and forth.
For example, if we have simp lemmas for f ∘ₗ g, then we want it to also apply for f ∘ₗ (g ∘ₗ h).
This was a TODO here: https://github.com/leanprover-community/mathlib4/blob/c99f041082f0d3896ed314ae1c865eb6dcff0c01/Mathlib/RingTheory/Coalgebra/Basic.lean#L363
But #34312 golfed it, so that TODO doesn't apply anymore. But I think it's a good thing to do.
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
Read Mathlib/RingTheory/Coalgebra/Basic.lean at the linked TODO and inspect the relevant LinearMap lemmas, along with the context from #34312. Done means the applicable lemmas have reassoc attributes so they also work with nested linear-map compositions without manual reassociation.
Written by the indexing model from the issue text.
Assessment
- Domain
- tooling
- Issue type
- Feature
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 55/100