Date: Mar 22, 2004 5:08 AM
Author: Chan-Ho Suh
Subject: Re: Hex Win Proof?

In article <>, Torben Ægidius Mogensen
<> wrote:

> (Bill Taylor) writes:

> > 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.

> The easy part is proving that both players can't win at the same time:
> Assume that there is a white path connecting top and bottom and a
> black path connecting left to right. These must intersect, but on a
> hex board two paths can only intersect if they share a hex.


Why must they intersect? That would seem to be the core of the proof.

The way I would show they intersect is to first show that a path
separates the board. But this is something that takes some work to