leanprover-community / leanprover-community/mathlib4
Add definition for `arcLength` and `pathEMetric` on a `PseudoEMetricSpace`
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Description
Port from mathlib3#18375. It is also possible to define 'length' using Hausdorff measure, zulipchat.
- #31766
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 reviewing mathlib3#18375 and the existing PseudoEMetricSpace definitions in mathlib4. Port the requested arcLength and pathEMetric definitions, then confirm the changes compile and address the checklist item in #31766.
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
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100