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From: desj@brahms (David desJardins)
Newsgroups: sci.math
Subject: Re: angels and devils
Message-ID: <226@cartan.Berkeley.EDU>
Date: Sun, 9-Nov-86 02:33:06 EST
Article-I.D.: cartan.226
Posted: Sun Nov  9 02:33:06 1986
Date-Received: Sun, 9-Nov-86 06:19:31 EST
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Reply-To: desj@brahms (David desJardins)
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In article <742@ukecc.UUCP> vnend@ukecc.UUCP writes:
>Keywords:Lets keep it simple....
> [Some ridiculous claim about destroying 2 pi R planets.]
>   The devil can trap a DUMB angel (random movement or some such garbage,
>remember the drunkards walk?) but he can't be guarenteed of trapping the
>angel unless he has the ability to destroy 2pi the angels movement. 

   I hate to be rude, but isn't it clear to all that this is not a proof?
It is not just this poster; several other people have said essentially the
same thing.  In sci.puzzle it might be appropriate to make random guesses
about what the solution might be.  It is definitely not appropriate in
sci.math.

   I certainly don't mean to discourage all speculation -- no one expects
a proof to spring forth fully formed.  For example, the discussion of what
happens if the angel if forced into a suboptimal move is appropriate (al-
though it would be nice to have a little more rigor in the analysis).  But
please try to make at least some attempt to understand the mathematical
subtleties of the problem before claiming to have proven a problem that
has resisted the efforts of some of the world's best mathematicians.
   As a suggestion, consider the problem of trapping a chess king.  It
definitely *can* be done.  If the king wins by reaching the edge of the
board, then he can be prevented from doing so if he starts at the center
of a board 35x35 or larger.  Understand this fact (by deriving it yourself,
or by reading the exposition of this and related problems in _Winning Ways_
ch. 19) before trying to solve a much harder problem.

   -- David desJardins