Zulip Chat Archive

Stream: Is there code for X?

Topic: Criterion for `set.finite` from finsets


Heather Macbeth (Jan 05 2022 at 20:08):

Looking for this lemma, or a slick proof!

import data.set.finite

example {β : Type*} {n : } (H :  (s : finset β), s.card  n) :
  (set.univ : set β).finite :=
sorry

Adam Topaz (Jan 05 2022 at 20:13):

import data.set.finite

example {β : Type*} {n : } (H :  (s : finset β), s.card  n) :
  (set.univ : set β).finite :=
begin
  haveI : fintype β := fintype_of_finset_card_le n H,
  exact set.finite_univ
end

Heather Macbeth (Jan 05 2022 at 20:13):

Nice, thanks!


Last updated: Dec 20 2023 at 11:08 UTC