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fix(library/data/set/finite): the powerset notation has already been fixed

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Leonardo de Moura 2015-08-16 18:47:20 -07:00
parent ea04414058
commit a06b288deb
1 changed files with 2 additions and 5 deletions
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library/data/set/finite.lean
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@ -129,11 +129,8 @@ by rewrite [-finset.to_set_upto n]; apply finite_finset
theorem to_finset_upto (n : ℕ) : to_finset {i | i < n} = finset.upto n :=
by apply (to_finset_eq_of_to_set_eq !finset.to_set_upto)
-- question: how can I avoid the parenthesis in the notation below?
-- this didn't work: notation `𝒫`:max s := powerset s, nor variants
theorem finite_powerset (s : set A) [fins : finite s] : finite (𝒫 s) :=
assert H : (𝒫 s) = finset.to_set '[finset.to_set (#finset 𝒫 (to_finset s))],
theorem finite_powerset (s : set A) [fins : finite s] : finite 𝒫 s :=
assert H : 𝒫 s = finset.to_set '[finset.to_set (#finset 𝒫 (to_finset s))],
from ext (take t, iff.intro
(suppose t ∈ 𝒫 s,
assert t ⊆ s, from this,