IsIntuitionistic should be generalised outside the `PL` scope, once we have typeclasses to express that a type possesses an implication connective.
Open
Nobody has claimed this yet.
- Dominant language
- Lean
- Stars
- 709
- Forks
- 200
- Avg merge
- 3d 6h
- Merged PRs (30d)
- 45
Description
/-- An inference system is intuitionistic if it derives ex falso quodlibet. TODO: this should be
generalised outside the `PL` scope, once we have typeclasses to express that a type possesses an
implication connective. -/
@[scoped grind]
class IsIntuitionistic (Atom : Type u) [Bot Atom] (S : Type*)
[InferenceSystem S (Proposition Atom)] where
/-- The principle of explosion (ex falso quolibet). -/
efq (A : Proposition Atom) : S⇓(⊥ → A)
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 at the IsIntuitionistic definition shown in the issue and inspect how the PL scope represents propositions and implication. Determine the typeclass design needed to express an implication connective independently of PL; done means the class is no longer tied to that scope while preserving the ex falso principle.
Written by the indexing model from the issue text.
Assessment
- Domain
- tooling
- Issue type
- Refactor
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100