Re: computer-go: Evaluating positions

[Don Dailey <drd@xxxxxxxxxxxxxxxxxxxxx>]

   Date: Thu, 21 Jun 2001 09:54:23 +0200

   On Wed, Jun 20, 2001 at 01:27:03PM -0400, Don Dailey wrote:
   > Absolute  ownership   of an
   > intersection means that a player is  guaranteed, with best play on his
   > part (but not  necessarily the opponents part) to  keep ownership of a
   > square without suffering any disadvantage.

   There is one even more absolute ownership concept that may come in helpful.
   There are points that are mine, and can not be taken away from me even if I
   only pass from now on. (eyes of a living group).

Good point.  This is a subset of absolute ownership, but another useful
definition and way of looking at things.


   > At the beginning of the game, a perfect  player can correctly say that
   > he  owns n squares  (n  depends on what  komi should  be to a  perfect
   > player) but he cannot  say which squares  they are.  But already, some
   > of these squares can be  assigned ownership status.  For instance  the
   > first player may  even be able to  claim  base ownership of  the whole
   > board (which  just means he can pick  any intersection he wants to and
   > have it in his control  at the end of  the game if he is  determined.)
   > Most of this ownership goes away as soon as he places the first stone.

   This is counter-intuitive. He owns less squares after he plays his stone?

I  used the term ownership  in order to get the  idea  across that the
player on the move may have the "option to own"  it.  But I think this
was a poor choice of  terminolgy.  I need a term  that means "right of
first choice."   This right alternates  on  each move because  you can
only claim so much on one turn, then the other guys turn.


   > Does any of this  have a practical use?  

   Interesting speculation, but I fear it is more relevant to the mathematical
   game of go than to the game we like to play in practice. It may be so that I
   can lay claim on one point at the opening, and keep it if I am really
   determined, but this sounds like a sure way to loose the game. 

We are bound completely by the mathematical game, I don't see how you can
distiguish the two.

Saying that you can lay claim to a  point forever is a definition, not
a  recommendation  for play.   It  a structural framework for thinking
about the game that is   mathematically unbiased and pure.  In   fact,
it's  probably a useful  distinction for this very  fact: it tells you
that a point is  not guranateed to be  worth  defending.  If we  could
actually detect this, it would be a useful thing to know and define.

I think this is also a concept we read  about in game annotations from
a very human   point of view where  a  player might be criticized  for
stubbornly holding a point to his detriment.

   Thinking in
   too absolute terms is bound to lead to inflexible playing. I think the point
   when you can start to agree on of who owns what is where the endgame starts.
   Earlier than that it all depends...

How we think  about things does  affect our viewpoint and we shouldn't
be too  inflexible, I agree.   But a point I want  to make  is that we
should not be  afraid of looking at things  from many different points
of view,  and one of the   points of view  I'm advocating  is based on
truth and beauty.   I'm all for  terminolgy like "white gives chase by
playing 19" but I would also  like to be  able to have  a way to think
about things that isn't based on ambiguity.

I have attempted to define a few terms  that are mathematically sound,
but I know in practice we cannot  easily apply these definitions, it's
beyond our power in most cases.  However,  I don't think that it hurts
to keep them in mind.  Good players aspire  to play the "best move" as
often as possible, even though they cannot always  do this.  But it is
not wrong for them to be aware that one or more best moves exist.


   > "Hot on the attack" does not map very well to anything useful to the
   > perfect player.

   True, but it does map well to the way humans play the game, and the way we
   look at the game, even if it is played between two very imperfect computers.
   I guess there will be a while before we can observe perfect players and see
   how they actually do it ;-)

Yes, these terms are very useful and map very well to the way we think
as humans.   I just like  to keep it in the  back of my mind that even
though these terms have real meaning to us, they are quite broken in a
purely mathematical sense.  I  have noticed that even stronger players
tend to eliminate in their  minds the irrelevant details in proportion
to their ability.  To  a very weak player a  very simple sequence  may
feel like he was "chased away", where a strong player may take it as a
glitch too uninportant to be viewed as a "chase."

It's the same  with "beauty."  Did you ever  play a beautiful game?  I
have played  beautiful  chess on  very rare occasions,   but I have no
formal method of "proving" this!  And yet I would never throw away the
concept of beauty, I still think it is a real thing.

I wonder  if that operation where they  took out the  right side of my
brain has anything to do with my viewpoints here?




     -H

   -- 
   Heikki Levanto  LSD - Levanto Software Development   <heikki@xxxxxxxxxxxxxxxxx>