leanprover-community / leanprover-community/mathlib4
Introduce a typeclass for a `ModelWithCorners` to be equal to `𝓘(𝕜, E)`
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Description
This typeclass (with instances for modelWithCornersSelf,
ModelWithCorners.prod, and ModelWithCorners.pi) will allow us to
add generic to_space/from_space conversions to MDiffContAt etc
instead of formulating lemmas like MDiffContAt.prod twice.
There is a big flaw in this proposal: we still have non-defeq ChartedSpace instances.
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
Review the proposed typeclass together with the named instances modelWithCornersSelf, ModelWithCorners.prod, and ModelWithCorners.pi. Check whether the non-definitional-equality ChartedSpace instances prevent the intended generic to_space/from_space conversions for MDiffContAt; done means resolving that flaw or establishing a viable revised proposal.
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