RE: computer-go: Live or Die

[Martin Mueller <mueller@xxxxxxxxx>]

>	BTW, I recall a diagram in your paper (the first or second diagram)
>where two similar positions where presented in a left-right symmetry. The
>only difference between the two was a single stone. One of the position was
>supposed to be safe, the other unsettled. Pardon me if I'm wrong but it
>seemed to me that the "safe" one was actually a ko. I'll have to check this,
>and I'll post my "solution" tomorrow.
>

Read out the situation again, very carefully :)

>> A region is a connected set of points on the Go board
>> which is surrounded by blocks of the same color.
>> A block is called enclosing block of a region if it
>> has at least one adjacent point that belongs to the region, and
>> at least one adjacent point that does not belong to the region.
>> The color of enclosing blocks is called the defender,
>> the other color is called the attacker.
>>
>> The interior of a region is the subset of points not adjacent
>> to an enclosing block.
>> There may be both attacker and defender stones in the interior.
>>
>	Well, I don't want to criticise these definitions; after all,
>everybody knows what "surrounded" means in Go. :).
>

You can be more formal if you like. Let s be the set of points not occupied
by stones of 'color', i.e. empty points plus opponent's stones. Then
regions are the connected components of s. Note that black regions and
white regions are completely different in this construction.

>	When I read your paper last year I was delighted to find ideas (that
>were new to me) about L&D recognition. Since then I have been trying to
>improve the definitions, scope and extend your ideas. I hope you don't mind
>a bit of (constructive) criticism of your paper. I'll post some remarks
>tomorrow (when I find my notes :).
>

That's the whole point of publishing stuff, to let others build on it. It
would be nice if you share your insights with the rest of us.

>	IMHO there are some loopholes in the way the criteria are worded. My
>concern is also about the completeness of the criteria defining what is
>known as "static" life (called "unconditional life"  in your paper). The
>word "unconditional" has been used to mean (too many) different things in Go
>literature.
>

Where exactly do you think are loopholes?

I make no claim that my static life criteria are complete. Go is much too
complicated for that :) But they should be correct.

"unconditional life" is a term defined by Benson, and he proves the
completeness of his method for recognizing unconditional life in his paper.

>	Are Thomas Wolf's papers available on the internet or in books ?
>
http://www.maths.qmw.ac.uk/~tw/public2.html#3

>	I find these topics fascinating !
>

Me too :)

	Martin