From: tcmay@got.net (Timothy C. May)
Date: Sat, 27 Jul 1996 07:00:04 +0800
To: cypherpunks@toad.com
Subject: Re: Twenty Bank Robbers -- Game theory:)
Message-ID: <ae1e490a020210044324@[205.199.118.202]>
MIME-Version: 1.0
Content-Type: text/plain


At 1:46 PM 7/26/96, David Lesher wrote:
>>
>> >``Twenty cypherpunks robbed a bank.''
>> >        ^^^^^^^^^^^^^
>> >I was careful choosing words.
>>
>> That was my reaction as well.  I'd assume that if twenty cypherpunks
>> rob a bank, either it's one of Eric's party games (:-), or else
>> they probably conspired over the net to rob a bank by computer.
>
>
>Will they ALL fit in Tim May's hot tub?

This is _my_ game-theoretic solution to the puzzle: let the 20 robbers
battle it out, kill each other, whatever, then invite the survivors over
and get rid of them all, leaving me with the money.

Though I've had to delete most of the discussion of this puzzle, some
things come to mind:

1. Similarities with "the unexpected hanging" problem. (Briefly, a man is
told he will be hung in the next 20 days. But out of sensitivity to his
feelings, he will not be hung if he can predict that he'll be hung on the
*next day*. The man points out that he cannot be hung on the 20th day, as
if he was still alive on the 19th day, he'd know that the 20th day was the
day of the hanging. Hence, no hanging on the 20th day. So there are 19 days
left. But the same logic applies, and so on, backward. He says smugly "I
can't be hanged at all." So he is surprises when he is hanged on the 13th
day.)

2. Inadequate accounting for or weighting of the "costs" of being killed.
(I think others, including Jim Bell that I saw, mentioned this.) An
abstract game theory problem is often hard to find a stable solution for,
and is all the more difficult when the stakes are so high and yet are
treated "abstractly."

3. The _iterated_ (repeated) form should have different results.


I initially dismissed the posed problem, but the dozens of responses
suggest that folks *do* find this stuff interesting.

--Tim May

Boycott "Big Brother Inside" software!
We got computers, we're tapping phone lines, we know that that ain't allowed.
---------:---------:---------:---------:---------:---------:---------:----
Timothy C. May              | Crypto Anarchy: encryption, digital money,
tcmay@got.net  408-728-0152 | anonymous networks, digital pseudonyms, zero
W.A.S.T.E.: Corralitos, CA  | knowledge, reputations, information markets,
Licensed Ontologist         | black markets, collapse of governments.
"National borders aren't even speed bumps on the information superhighway."