Zulip Chat Archive
Stream: lean4
Topic: How to name this lemma?
François G. Dorais (Nov 20 2023 at 20:59):
What would be a good name for this lemma?
import Std
open Ordering
theorem name_me {x y : Ordering} : swap x = y ↔ swap y = x := sorry
Kyle Miller (Nov 20 2023 at 21:03):
I think this would usually be phrased as swap x = y ↔ x = swap y
and be named something like swap_eq_iff
Kyle Miller (Nov 20 2023 at 21:05):
That's shorting the longer name swap_eq_iff_eq_swap
. An analogue in mathlib is docs#inv_eq_iff_eq_inv
Kyle Miller (Nov 20 2023 at 21:05):
Then there's also swap x = swap y ↔ x = y
, which would be named swap_inj
François G. Dorais (Nov 20 2023 at 21:14):
Ah! Yes, it's like an adjunction. I like this!
Last updated: Dec 20 2023 at 11:08 UTC