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Topic: Hex Win Proof?
Replies: 41   Last Post: Mar 24, 2004 6:39 PM

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 Brian Chandler Posts: 1,899 Registered: 12/6/04
Re: Hex Win Proof?
Posted: Mar 19, 2004 2:09 AM

w.taylor@math.canterbury.ac.nz (Bill Taylor) wrote in message news:<716e06f5.0403181938.72a82f90@posting.google.com>...
> It is an old theorem that in Hex, once the board has been completely
> filled in with two colours, there *must* be a winning path for one
> or other of them.
>
> Now, I can prove this easily enough mathematically, but I'm wondering if
> there is a simple proof, or proof outline, that would be understandable
> and reasonably convincing to the intelligent layman.
>
> Can anyone help out please?

Imagine the board tipped up, so player A goes from top to bottom,
player B from left to right. Suppose the board is actually two sheets
of clear plastic, and two players have "stones" of white sugar (A) and
red granite (B), and moreover these stones "plug" the hexagon cells
(in the obvious way).

Now pour water in at the top. Either it dissolves through the sugar
and reaches the bottom, in which case A has a path, or it doesn't, in
which case there must be a continuous boundary of impervious granite,
and B has a path.

(Does this help? I think it does (slightly) use some facts about the
behaviour of liquids to help the imagination along.)

Brian Chandler
http://imaginatorium.org

Date Subject Author
3/18/04 Bill Taylor
3/18/04 Tim Brauch
3/19/04 Brian Chandler
3/19/04 Jonathan Welton
3/19/04 Tim Brauch
3/19/04 Richard Henry
3/20/04 Glenn C. Rhoads
3/20/04 Chan-Ho Suh
3/21/04 Arthur J. O'Dwyer
3/19/04 Bob Harris
3/19/04 Tim Smith
3/19/04 Dvd Avins
3/20/04 Nate Smith
3/20/04 Chan-Ho Suh
3/20/04 G. A. Edgar
3/19/04 Richard Henry
3/19/04 Steven Meyers
3/20/04 Nate Smith
3/20/04 Larry Hammick
3/20/04 Tim Smith
3/20/04 Glenn C. Rhoads
3/20/04 Glenn C. Rhoads
3/21/04 Steven Meyers
3/22/04 Glenn C. Rhoads
3/22/04 Torben Mogensen
3/22/04 Chan-Ho Suh
3/22/04 Torben Mogensen
3/22/04 Chan-Ho Suh
3/23/04 Torben Mogensen
3/23/04 Robin Chapman
3/23/04 Chan-Ho Suh
3/24/04 Robin Chapman
3/24/04 Tim Smith
3/24/04 Robin Chapman
3/24/04 Tim Smith
3/24/04 Jon Haugsand
3/22/04 Andrzej Kolowski
3/23/04 Alexander Malkis
3/23/04 Chan-Ho Suh
3/23/04 Dr. Eric Wingler
3/24/04 Danny Purvis
3/24/04 Danny Purvis