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Subject: Re: Conspiracy -- conshmiracy

Author: Dann Corbit

Date: 15:55:42 01/19/00

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On January 19, 2000 at 18:34:52, blass uri wrote:
[snip]
>The question is if the move of deeper blue was the right move.
>It is not clear that 36.axb5 was the right move.
So the argument against 36.axb5 was that it is not such a good move?
Every program has bugs.  There are a very large number of tunable parameters
with the deep blue machine.  Perhaps one (or many) of them was not optimal.

>If it is not the right move then the expression solve for finding axb5 is not
>the right expression.
>
>It is possible that it found this move because of a bug because I saw no tree
>that prove to computers that axb5 is the right move.
There are lots of moves that computers cannot verify.  They cannot verify the
NOLOT positions, for instance.  If we saw the output of Deep Blue on the NOLOT
positions and did not have SuperGM analysis already available, a lot of us would
think the analysis was wrong or there might be a bug.

>The case with the nolot positions is different because I think that there is a
>tree to prove the solutions(it is easy for programs to see that playing moves
>not in the tree is bad).
I don't believe in any tree to prove solutions unless it leads to checkmate.  A
deeper analysis can always reveal a better move.  Indeed, the analysis for the
"... Goes Deep" articles in the computer chess journal shows that there is about
a 17% chance of improvement for each new ply.  That means that the odds that we
keep the current selection is (1-0.17) = 0.83.  So after two plies, the odds are
.83*.83 = 0.6889, after 3 plies it is 0.571787.  After ten more plies it is
0.1551604118721 or only about 16% chance that we keep the same move.

A five year old looks at a chess board. He sees that he can take the pawn.  His
big brother set up a trap to take the bishop.  But his dad is watching and sees
a forced mate and kibitzes (he feels sorry for the 5 year old).

As we move up the ladder, the more deeply we see, the better our choices.  I
don't think it will ever stop getting better until you can see all the way to
checkmate.

In other words, all analysis is tenative.  Unless it leads directly to forced
checkmate.



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