Post #1816226
2026-02-22 18:26 UTC
@oantolin Nice!
@dwarn
Replies (1)
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@oantolin@mathstodon.xyz 2026-02-22 19:26
@MartinEscardo Oh, now that I've looked at @dwarn's MathOverflow link, I see this counterexample is a special case of the one he gives there: for finite abelian group of odd order you can use (x,y) |--> (x+y)/2, which is even more clearly idempotent.