From: Steve Reid <root@edmweb.com>
Date: Fri, 26 Jul 1996 15:11:13 +0800
To: ichudov@galaxy.galstar.com
Subject: Twenty Bank Robbers -- Game theory:)
Message-ID: <Pine.BSF.3.91.960725173009.186A-100000@bitbucket.edmweb.com>
MIME-Version: 1.0
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> Twenty cypherpunks robbed a bank. They took 20 million bucks. Here's
> how they plan to split the money: they stay in line, and the first guy
> suggests how to split the money. Then they vote on his suggestion. If
> 50% or more vote for his proposal, his suggestion is adopted.
> Otherwise they kill the  first robber and now it is the turn of guy #2
> to make another splitting proposal. Same voting rules apply.

I don't know the final outcome, but I do have a couple of observations...

- The person at the front of the line, making the suggestion, will always
vote for his own proposal, if only to save his own life. This is obvious. 

- The second-to-last person is in an interesting position. If everyone
before him is dead and he gets to the front of the line, he will decide
that he gets _all_ of the money for himself. If there's only two people
left, his own Yes vote for his own proposal makes 50% and he automatically
gets all the money. This is the best possible deal for him. So, I think
the second-to-last person will vote No to every proposal except his own, 
in an effort to force this situation.


Now that I think about it, solving this 'game theory' scenario has some
parallels to cryptanalysis (disclaimer: I am not a cryptanalyst). By
pointing out the above properties, I've removed a couple of 'bits' from
the 'search space'. 


=====================================================================
| Steve Reid - SysAdmin & Pres, EDM Web (http://www.edmweb.com/)    |
| Email: steve@edmweb.com   Home Page: http://www.edmweb.com/steve/ |
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|          -- Disclaimer: JMHO, YMMV, TANSTAAFL, IANAL. --          |
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