feat: logical equivalence for modal logic#535
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Co-authored-by: Chris Henson <46805207+chenson2018@users.noreply.github.com>
Co-authored-by: Chris Henson <46805207+chenson2018@users.noreply.github.com>
thomaskwaring
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some minor comments but lgtm on the whole!
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Thanks, @thomaskwaring. All done! |
chenson2018
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Co-authored-by: Chris Henson <46805207+chenson2018@users.noreply.github.com>
Co-authored-by: Chris Henson <46805207+chenson2018@users.noreply.github.com>
Co-authored-by: Chris Henson <46805207+chenson2018@users.noreply.github.com>
Co-authored-by: Chris Henson <46805207+chenson2018@users.noreply.github.com>
Co-authored-by: Chris Henson <46805207+chenson2018@users.noreply.github.com>
chenson2018
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Two comments below about notation lemmas that need to be extracted, but I'm going to go ahead and approve so you're not waiting on me.
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@chenson2018 I've extracted the lemmas, but I do wonder about the direction we state these |
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Adds logical equivalence for modal logic, proving that it is a `Congruence` (for any modal logic, regardless of the class of models considered) and a `LogicalEquivalence` (for logic K, i.e., when considering the class of all models). The PR also renames `Proposition.neg` to `Proposition.not` and adds a useful lemma on `Proposition.iff`. Depends on leanprover#528. --------- Co-authored-by: Chris Henson <46805207+chenson2018@users.noreply.github.com>
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Diplomatic PR description for Modal/ formula primitives refactoring, stacking on PR leanprover#648. Coordinates with PRs leanprover#607, leanprover#528, leanprover#535, leanprover#649. Session: sess_1781535860_c7d8e9
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Adds logical equivalence for modal logic, proving that it is a
Congruence(for any modal logic, regardless of the class of models considered) and aLogicalEquivalence(for logic K, i.e., when considering the class of all models).The PR also renames
Proposition.negtoProposition.notand adds a useful lemma onProposition.iff.Depends on #528.