Talk:Josephus problem

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 Field: Applied mathematics (historical)


Near the end, the article says "Therefore, if we represent n as 2m + l, where 0 < = l < 2m, then f(n) = 2 * l + 1." I think the m's should be n's; there's no m in the problem. --ngb

You are correct that there is no m in the statement of the problem. The variables m and l are being defined in the sentence: "if we represent n as 2^m + l, where 0 < = l < 2^m, then f(n) = 2 * l + 1." Since m does not appear in the solution, we could also say, "let l be the result when we subtract from n the largest power of 2 no greater than n." Ptrillian 11:19, 2 January 2007 (UTC)

It seems like a good idea to merge the Josephus_permutation article into this article. If no one objects, I will plan to do it within a few days. Ptrillian 12:42, 2 January 2007 (UTC)

Yea this should be merged.Styracosaurus 00:30, 27 January 2007 (UTC)


The setting of this problem is legendary at best. In Josephus' own account (The Jewish War, III.8.viii), the order of executions is by lot, not skipping around the circle. This ought to be mentioned somewhere in the article. Willy Logan 01:10, 22 January 2007 (UTC)

Somebody changed it that way, however, the article is currently quite nonsensical, since the History part has nothing in common whatsoever with the problem. We need to find out why the name, who named it like that (if the real history does not contain anything similar), or something. --Mormegil (talk) 14:44, 15 January 2008 (UTC)
The way it is described in the article has barely anything to do with what (according to Josephus) happened. He wasn't there himself, it wasn't a cave but a fortress and no one survived. See Masada. -- (talk) 19:08, 1 September 2008 (UTC)
No, we're talking about the siege of Yodfat. The siege of Masada took place years after Josephus's surrender. Other than that, the story is very related to the problem. Whether it is necessary to make it so long is another problem.-- (talk) 22:15, 9 May 2011 (UTC)

Complete muddle[edit]

This article is very muddled. First it explains the problem with a general example that is concrete ("people are waiting to be executed"). Then it gives a "history" which is actually a source legend with a specific example ("he and his 40 comrades...a step of three"). Then it gives a proof that uses a different specific example ("we explicitly solve the problem when every second person will be killed"). But in no case does it actually give the answer. I believe the answer for the Josephus example of 41 participants and a step of three is that position 31 is the survivor and position 16 is the next-to-last. But does any source state this for citation purposes? --Tysto (talk) 02:09, 19 April 2009 (UTC)

Also, it's very unencyclopaedic to develop the solution in a chatty style. Give the answer in a concise way, and make it possible for people to skip the proof, it they don't want to read it, but just want to reference the solution.-- (talk) 19:53, 14 September 2011 (UTC)

Length of a josephus game[edit]

Long time ago I made the A112088 integer sequence that somehow is related to the josephus problem, which I have never heard of until now. So I am not the right person to write anything about it. Here is the talk about it Rainer Rosenthal, Josephus climbing binary trees?. Also Rainer Rosenthal, Rundenzaehlung im Josephus Spiel. —Preceding unsigned comment added by Simon Strandgaard (talkcontribs) 21:17, 19 May 2009 (UTC)

Proof of theorem wrong[edit]

In the case of n odd, the proof gets that f(n) = 2((2l1) + 1) + 1 = 2l + 1. This is clearly wrong. GlennHK (talk) 08:51, 1 May 2012 (UTC)

Useless example code[edit]

The example code isn't really useful. It uses a language feature only present in Java, and it's easily describable by some mathematical expression. Could we remove it? Simplyianm (talk) 05:22, 25 November 2016 (UTC)