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[Merged by Bors] - feat(data/nat/pairing): add some nat.pair
lemmas
#8740
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JasonKYi
commented
Aug 18, 2021
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] | ||
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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
bors r+ |
Pull request successfully merged into master. Build succeeded: |
nat.pair
lemmasnat.pair
lemmas