Dupe of big FAQ on the hot network list, with (poor) dupe answer by high rep user. Of course the fact that cyclic groups satisfy the converse of Lagrange's theorem is proved in many prior answers. Not clear how to best handle this, but I think we should do all we can to discourage such duplicate answers (esp. by frequent offenders), since linking to prior answers will yield much richer knowledge for the questioner. Any group theorists here?

@BillDubuque What "big FAQ" to you propose the the duplicated post? It would have helped if you had voted to close as a dupe. I'd be happy to close, if you can identify the duplicated post.

@BillDubuque Never mind; I found a dupe, and the post is now closed.

@amWhy I'm sure there are many users more familiar than I with the group theory part of this site. So I leave it to them to best organize such dupes.

Bountied PSQ: math.stackexchange.com/q/4882534

C1

C PSQ and likely dupe

@XanderHenderson Is-useful: math.stackexchange.com/q/4884782

D2

D3

C Prior closed dupe was wrongly reopened by the lone answerer - as they have done several times in the past.

^^^ This is a good dupe target (it was used but strangely is not in the linked questions)

@Ѕᴀᴀᴅ Thanks.

please close/downvote/delete this duplicate

please delete

@Feeds already two undelete-votes. Unfortunately , I accidently retracted my vote to delete the request.

please delete and also help to delete the corresponding question

@Peter Please do not vote to delete answers to the Reopen & Undelete thread.

You are welcome to downvote, or to comment to express disagreement, but voting to delete is a violation of the spirit of that thread.