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[Merged by Bors] - feat(data/nat/pairing): add some nat.pair lemmas #8740

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JasonKYi
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@JasonKYi JasonKYi added the awaiting-review The author would like community review of the PR label Aug 18, 2021
Comment on lines +138 to +144
lemma supr_unpair {α} [complete_lattice α] (f : ℕ → ℕ → α) :
(⨆ n : ℕ, f n.unpair.1 n.unpair.2) = ⨆ i j : ℕ, f i j :=
by rw [← (supr_prod : (⨆ i : ℕ × ℕ, f i.1 i.2) = _), ← nat.surjective_unpair.supr_comp]

lemma infi_unpair {α} [complete_lattice α] (f : ℕ → ℕ → α) :
(⨅ n : ℕ, f n.unpair.1 n.unpair.2) = ⨅ i j : ℕ, f i j :=
supr_unpair (show ℕ → ℕ → order_dual α, from f)
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In your original application did you want the Union version? If so, you should probably add that one below these (proved in terms of them).

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Can I not directly apply the supr version in my use case?

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Not with a rw. It will work with an apply

@eric-wieser
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bors r+

@github-actions github-actions bot added ready-to-merge All that is left is for bors to build and merge this PR. (Remember you need to say `bors r+`.) and removed awaiting-review The author would like community review of the PR labels Aug 18, 2021
bors bot pushed a commit that referenced this pull request Aug 18, 2021
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bors bot commented Aug 18, 2021

Pull request successfully merged into master.

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@bors bors bot changed the title feat(data/nat/pairing): add some nat.pair lemmas [Merged by Bors] - feat(data/nat/pairing): add some nat.pair lemmas Aug 18, 2021
@bors bors bot closed this Aug 18, 2021
@bors bors bot deleted the JasonKYi/unpair_lemmas branch August 18, 2021 21:30
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2 participants