[Merged by Bors] - feat(set_theory/cardinal/basic): lemmas about #(finset α)
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| lemma mk_finset {α : Type u} {s : finset α} : #s = ↑(finset.card s) := by simp | ||
| lemma mk_of_finset {α : Type u} {s : finset α} : #s = ↑(finset.card s) := by simp | ||
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| lemma mk_finset_of_fintype [fintype α] : #(finset α) = 2 ^ℕ fintype.card α := by simp |
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Can you squeeze this simp, for the sake of making it clear which lemmas this uses?
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This simp basically just turns #(finset α) into fintype.card (finset α), for which the lemma stating that it's equal to 2 ^ fintype.card α already exists. A few other proofs in this file, like mk_fin, mk_bool, mk_Prop, use this same technique and are not squeezed.
Should I squeeze it anyways?
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I think that non-squeezed simps are OK as long as they're fast.
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Thanks! |
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This PR does the following: - prove `mk_finset_of_fintype : #(finset α) = 2 ^ℕ fintype.card α` for `fintype α` - rename `mk_finset_eq_mk` to `mk_finset_of_infinite` to match the former - rename `mk_finset` to `mk_coe_finset` to avoid confusion with these two lemmas
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#(finset α)#(finset α)
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This PR does the following: - prove `mk_finset_of_fintype : #(finset α) = 2 ^ℕ fintype.card α` for `fintype α` - rename `mk_finset_eq_mk` to `mk_finset_of_infinite` to match the former - rename `mk_finset` to `mk_coe_finset` to avoid confusion with these two lemmas
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This PR does the following:
mk_finset_of_fintype : #(finset α) = 2 ^ℕ fintype.card αforfintype αmk_finset_eq_mktomk_finset_of_infiniteto match the formermk_finsettomk_coe_finsetto avoid confusion with these two lemmas