Zulip Chat Archive

Stream: Is there code for X?

Topic: Nontrivial term of nontrivial type


Oliver Nash (Jun 27 2023 at 18:46):

Is this really missing:

@[to_additive]
lemma exists_ne_one (G : Type _) [Group G] [Nontrivial G] :  (g : G), g  1 := by
  obtain x, y, h := exists_pair_ne G
  exact x / y, Iff.mpr div_ne_one h

Johan Commelin (Jun 27 2023 at 18:48):

I think that for every x, you should be able to get a y that is unequal to it.

Johan Commelin (Jun 27 2023 at 18:49):

That lemma should exist, and it doesn't need algebraic structure.

Sebastien Gouezel (Jun 27 2023 at 18:49):

docs#exists_ne

Oliver Nash (Jun 27 2023 at 18:52):

Right, thanks!


Last updated: Dec 20 2023 at 11:08 UTC