leanprover-community / leanprover-community/iris-lean
Experiment: Qp to Rat
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- Dominant language
- Lean
- Stars
- 218
- Forks
- 63
- Avg merge
- 1d 23h
- Merged PRs (30d)
- 22
Description
PR #443 replaces the frac hierarchy with a single type Qp. Since Qp is a subtype of Rat, its automation around the arithmetic tactics is worse. An alternative is to use the type Rat, and bake positivity into the validity predicate of Frac. Doing so has the potential to clean up some annoying coercion lemmas, at the cost of potentially needing to do Iris reasoning whenever the positivity of a fraction is required.
Once we have more in-depth usages of Frac we should re-evaluate to see if this is the better solution for Lean's automation suite.
Contributor guide
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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 PR #443 and the current uses of Qp, Rat, and Frac. Compare how the two proposed representations affect arithmetic tactic automation, coercion lemmas, and the need for Iris reasoning around positivity. Done means producing enough usage-based evidence to decide which representation works better.
Written by the indexing model from the issue text.
Assessment
- Domain
- devtools
- Issue type
- Refactor
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Quiet
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100